Phase 2 Randomized Clinical Study of Netarsudil Ophthalmic Solution in Japanese Patients with Primary Open-Angle Glaucoma or Ocular Hypertension

Introduction Netarsudil reduces intraocular pressure (IOP) by increasing aqueous outflow through the trabecular meshwork (TM) pathway and decreasing episcleral venous pressure. The primary objective of this phase 2 study was to evaluate ocular hypotensive efficacy and safety of three netarsudil concentrations (0.01%, 0.02%, and 0.04%) relative to its placebo over 4 weeks in Japanese patients with primary open-angle glaucoma (POAG) or ocular hypertension (OHT). Methods Patients were randomized to one of four treatment arms, netarsudil ophthalmic solution 0.01%, 0.02%, 0.04%, or placebo, and treated once-daily (QD) in the evening (p.m.) for 4 weeks. The primary efficacy variable was mean diurnal IOP (average of diurnal time points at 9 a.m., 11 a.m., and 4 p.m.) at week 4. Results A total of 215 patients were randomized and 207 (96.3%) completed the study. The mean of mean diurnal IOP at baseline ranged from 20.28 to 21.14 mmHg across groups. At week 4, least squares (LS) mean of mean diurnal IOP adjusted for baseline was 16.53, 15.82, 16.06, and 18.94 mmHg in the netarsudil 0.01%, 0.02%, 0.04%, and placebo groups, respectively, demonstrating the superiority of netarsudil (all concentrations) over placebo. At week 4, mean reduction (mean percentage reduction) from baseline in mean diurnal IOP was 4.10 (19.8%), 4.80 (23.5%), 4.81 (23.8%), and 1.73 mmHg (8.2%), respectively, demonstrating statistically significant reductions (p < 0.0001) in all netarsudil concentrations over placebo. Adverse events (AEs) occurred in a concentration-dependent manner, and the incidence of ocular AEs was 34.5%, 42.6%, 68.6%, and 9.1% in the netarsudil 0.01%, 0.02%, 0.04%, and placebo groups, respectively. The most frequently reported AE was conjunctival hyperemia, with an incidence of 23.6%, 37.0%, 56.9%, and 1.8%, respectively. No serious AEs were reported. Conclusion Netarsudil ophthalmic solutions 0.01%, 0.02%, and 0.04% dosed QD (p.m.) demonstrated superiority to placebo in terms of hypotensive effectiveness at week 4 and were found to be safe and generally well tolerated. Netarsudil 0.02% QD provided an optimal efficacy and safety profile for the treatment of Japanese patients with POAG or OHT.