Background: Several studies have investigated the effect of latanoprost on intraocular pressure (IOP). We compared the IOP-lowering effects of three higher concentrations of latanoprost with the commercially available concentration of 0.005% (50 μg/mL) in patients with primary open-angle glaucoma or ocular hypertension.
Methods: Treatment-naive subjects or those receiving IOP-lowering medication with baseline IOP levels of ≥ 24 mmHg and ≤ 36 mmHg in at least one eye after washout were randomized to receive an evening dose of latanoprost 50, 75, 100, or 125 μg/mL for 4 weeks. At weeks 1, 2, 3, and 4, ocular examinations were performed and IOP was measured. Ocular symptoms and adverse events were monitored. The primary efficacy endpoint was the change in IOP from baseline to week 4 at 8 a.m. and 4 p.m. for the per protocol (PP) population using a "worse eye" analysis. Secondary efficacy endpoints were change in IOP at each time point from baseline across all visits, and percentage change in IOP from baseline to week 4 at 8 a.m.
Results: In all, 282 patients were randomized and treated; 274 were included in the PP population. Treatment groups were similar at baseline; 68% were diagnosed with primary open-angle glaucoma. Mean baseline IOP levels were comparable across treatments. There were no statistically significant differences in IOP reductions from baseline to week 4 at either time point between those treated with higher concentrations of latanoprost versus those receiving 50 μg/mL. Least squares mean IOP changes at 8 a.m. were -10.13, -9.59, -10.02, and -9.06 mmHg for latanoprost 50, 75, 100, and 125 μg/mL, respectively, and at 4 p.m. were -8.90, -8.29, -8.81, and -8.34 mmHg, respectively. Results of secondary efficacy analyses supported those of the primary analysis. Conjunctival hyperemia, the most commonly reported adverse event, occurred in 16.9%, 18.6%, 20.8% and 15.9% of subjects receiving latanoprost 50, 75, 100, and 125 μg/mL, respectively.
Conclusions: IOP reductions were observed in all treatment groups postbaseline, with no clinically relevant or statistically significant differences detected favoring any of the higher concentrations of latanoprost compared with latanoprost 50 μg/mL. All doses of latanoprost were well tolerated.
Trial registration: Clinical Trials.gov Identifier NCT01379144.