['This study investigated the efficacy and safety of tafluprost as an adjunctive therapy to timolol in patients with open-angle glaucoma or ocular hypertension, uncontrolled by timolol monotherapy.', 'This was a randomized, double-masked, parallel-group, multinational and multicenter 12-week phase III study. Tafluprost 0.0015% (once daily: 20:10) or vehicle were administered as adjunctive therapy to timolol 0.5% (twice daily: 08:00 and 20:00) for 6 weeks, after which all patients received tafluprost for 6 weeks. Intraocular pressure (IOP) measurements were conducted at 08:00, 10:00, and 16:00 at baseline, and weeks 2, 4, 6, and 12.', 'A total of 185 patients were randomized to tafluprost (n = 96) or vehicle (n = 89). Reductions in IOP were seen in both groups, which were consistently more pronounced with tafluprost. At week 6, the change from baseline in diurnal IOP ranged from -5.49 to -5.82 mmHg, and the overall treatment difference (tafluprost vehicle) was -1.49 mmHg (upper 95% confidence interval, -0.66; p<0.001, intention-to-treat population, repeated measurements of the analysis of covariance model). At week 12, the change from baseline ranged from -6.22 to -6.79 mmHg in the tafluprost group. Patients switched from vehicle to tafluprost achieved a similar decrease in IOP to those who received tafluprost throughout the study (group difference at 12 weeks, -0.09 mmHg, p=0.812). There were more ocular adverse events with tafluprost compared with vehicle (42% vs. 29%, respectively), but most were mild in severity.'] Does adjunctive use of tafluprost with timolol provide additive effects for reduction of intraocular pressure in patients with glaucoma?