24-hour control of intraocular pressure with 2% dorzolamide/0.5% timolol fixed-combination ophthalmic solution in open-angle glaucoma.

Objective: To evaluate the 24-hour efficacy and tolerability of 2% dorzolamide/0.5% timolol fixed combination (DTFC) solution in open-angle glaucoma and ocular hypertension.

Research Design And Methods: Randomized, parallel, double-masked, multicenter study. Patients with insufficiently controlled intraocular pressure (IOP > or = 22 mmHg) were randomized to DTFC (N = 117) or timolol (N = 115). IOP was measured at baseline, 6 weeks, and 8 weeks, with measurements taken at 6 p.m., 8 p.m., 10 p.m., 2 a.m., 6 a.m., 8 a.m., 10 a.m., and 2 p.m. ClinicalTrials. gov identifier: NCT00108017 MAIN OUTCOME MEASURES: Statistically significant change in IOP from untreated baseline for DTFC at all hours at week 8. Secondary outcome measures included: IOP-lowering at week 6 at all individual time points, change from baseline to 8 weeks in mean daytime IOP (average of 8 a.m., 10 a.m., 2 p.m., 6 p.m., and 8 p.m. IOPs) and night-time IOP (10 p.m., 2 a.m., 6 a.m.), and comparison of DTFC with timolol after 8 weeks.

Results: Patients receiving DTFC had a statistically significant and clinically relevant reduction in IOP at week 8 compared with baseline at all eight time points (p < 0.001). Significant IOP reductions were also seen at all time points at week 6 (p < 0.001). DTFC significantly lowered mean daytime IOP and night-time IOP ( p < 0.001 for both). Timolol alone also significantly reduced IOP from baseline at 8 weeks for all diurnal time points, and mean daytime and night-time IOP ( p < 0.001 for all). Compared with timolol alone, there were significantly greater reductions with DTFC at 10 a. m. (p = 0.003) and 2 p. m. (p = 0.016), and for mean daytime IOP (p = 0.025) at 8 weeks. Significant between-treatment differences were not observed at other time points. Both treatments were well-tolerated, with no differences observed in the safety profiles between the treatment groups.

Conclusions: Both DTFC and timolol provided significant IOP reduction over the entire 24-hour measurement period. Although this study was not designed or powered to compare DTFC and timolol, DTFC exhibited greater IOP-lowering than timolol during the daytime, but not at night.