Comparison of the diurnal ocular hypotensive efficacy of travoprost and latanoprost over a 44-hour period in patients with elevated intraocular pressure.

BACKGROUND

Prostaglandin analogues are effective ocular hypotensive agents and are being used increasingly in the treatment of elevated intraocular pressure (IOP). These agents are typically dosed once daily.

OBJECTIVES

A pilot study was conducted to evaluate the duration of travoprost's IOP-lowering efficacy up to 84 hours after the final dose in patients with open-angle glaucoma. A follow-up study was conducted to compare diurnal IOP control with travoprost and latanoprost over a 44-hour period.

METHODS

In the open label pilot study, patients received 0.004% travoprost in both eyes at 8 pm daily for 2 weeks. After 2 weeks, IOP was measured before administration of the last daily dose, every 4 hours thereafter for 36 hours, and 60 and 84 hours after the last dose, with no additional ocular hypotensive medication given. In the controlled, double-masked, parallel-group, follow-up study, patients were randomized to self-administer 1 drop of the marketed doses of 0.004% travoprost or 0.005% latanoprost in both eyes at 8 pm daily for 2 weeks. At the end of this period, patients returned to the facility at approximately 8 pm for IOP measurement and administration of the final dose of study medication. IOP was then measured at 4-hour intervals for 44 hours after the last dose, with no additional ocular hypotensive medication given.

RESULTS

The pilot study included 21 patients (67% female, 33% male; age range, 35-81 years) with open-angle glaucoma. IOP values were significantly below baseline at all time points up to 84 hours after the final dose of travoprost ( P<0.001). The follow-up study enrolled 35 patients, 1 of whom was excluded for missing data; thus, the intent-to-treat analysis included 34 patients (68% female, 32% male; age range, 36-72 years). At the unmedicated eligibility visit, mean IOP over 24 hours ranged from 21 to 26 mm Hg in each treatment group. After 2 weeks of treatment and 24 hours after the last dose, mean (SD) IOP was 13.1 (2.1) mm Hg (change from eligibility visit, -10.4 [2.7] mm Hg) in the travoprost group and 16.0 (3.1) mm Hg (change from eligibility visit, -7.1 [2.4] mm Hg) in the latanoprost group. The difference in change from baseline was statistically significant between treatment groups (P=0.006). Travoprost lowered IOP significantly at all time points throughout the 44-hour period after the last dose (mean IOP, <or=18 mm Hg; [P<0.001) and was statistically superior to latanoprost at 8 pm before the last dose (P=0.041) and 24 hours after the last dose (P=0.006). Latanoprost showed greater IOP-lowering efficacy compared with travoprost 4 hours after the last dose (P=0.040). IOP reductions were significantly different from zero at all time points with both treatments (P<0.001).

CONCLUSIONS

The results of the pilot study suggest that travoprost produces reductions in IOP that may be sustained for up to 84 hours after dosing. The results of the follow-up study suggest that both prostaglandin analogues significantly lower IOP from baseline in patients with open-angle glaucoma and provide excellent diurnal IOP control throughout a 24-hour period.