Hypotensive Effect of Latanoprost/Timolol Versus Travoprost/Timolol Fixed Combinations in NTG Patients: A Randomized, Multicenter, Crossover Clinical Trial

Abstract

Citation: Shoji T, Sato H, Mizukawa A, et al. Hypotensive effect of latanoprost/timolol versus travoprost/timolol fixed combinations in NTG patients: a randomized, multicenter, cross-over clinical trial. Invest Ophthalmol Vis Sci. 2013;54:6242-6247. DOI:10.1167/iovs.13-11942 PURPOSE. To compare the ocular hypotensive effect of travoprost plus timolol (TTFC) and latanoprost plus timolol fixed combinations (LTFC) in patients with normal-tension glaucoma (NTG). METHODS. A two-sequence 12-week, multicenter, prospective, randomized, single-blinded, crossover clinical trial examined 59 NTG patients. If both eyes were eligible, only one eye (chosen at random) was used for analytical purposes. After a 12-week run-in period with dorzolamide plus timolol fixed combination (DTFC), patients were randomized into one of the two crossover sequences of treatment for 12 weeks with TTFC or LTFC and were subsequently crossed over to the alternative treatment for a further 12 weeks. The primary endpoint was reduction in IOP after 12 weeks of each treatment sequence. The effect of treatment on IOP was assessed using a linear mixed model. RESULTS. The mean baseline IOP was 14.8 6 3.3 mm Hg (95% confidence interval [CI], 14.1-15.3 mm Hg) for treatment with DTFC. The TTFC treatment period showed consistently lower mean IOP compared with LTFC treatment period at all measurement time points. Mean reduction in IOP at 12 weeks was significantly greater in the TTFC group than in the LTFC group (À2.4 6 2.3 mm Hg vs. À1.1 6 2.3 mm Hg; P ¼ 0.021). No interaction between the drug and treatment sequence was detected. The effects of intraocular lens implantation and measurement time were also not significant. The tolerability profiles of both treatments were similar. CONCLUSIONS. The additional reduction in IOP was greater with TTFC than with LTFC, and their tolerability profiles were similar. (http://www.umin.ac.jp/ctr/ number, UMIN 000005974.) Keywords: fixed combination, normal-tension glaucoma, randomized study G laucoma is one of the main causes of blindness and irreversible deterioration of vision worldwide. 1 It affects approximately 70 million people and is the leading cause of irreversible blindness in approximately 10% of those affected. Approximately half of all patients with glaucoma live in East Asia. 5 Normal-tension glaucoma is often used to describe patients with open-angle glaucoma when their untreated IOP is maintained within a statistically normal range. Multicenter clinical trials have confirmed the importance of reducing IOP in patients with POAG and NTG, 8 When two drugs are required to control IOP, there are a number of potential advantages to using a fixed combination, including no risk of drug washout, 9 reduced exposure to preservatives, and ultimately better patient compliance and quality of life. 10 To our knowledge, few studies are available 11 that compare these fixed combinations in Asian patients, particularly those with NTG. Travoprost plus timolol (TTFC) and latanoprost plus timolol fixed combinations (LTFC) are prostaglandin/timolol fixed combinations medication currently available in Japan. Thus, the purpose of the present study was to compare the ocular hypotensive effect of LTFC and TTFC in glaucoma patients not fully controlled with monotherapy