Intraocular Pressure–Lowering Effects and Safety of Topical Administration of a Selective ROCK Inhibitor, SNJ-1656, in Healthy Volunteers

Objective: To investigate the effects and safety of topical administration of an ophthalmic solution of a selective Rho-associated coiled coil-forming protein kinase (ROCK) inhibitor, SNJ-1656, 0.003% to 0.1%, in healthy male adult volunteers.Design: Randomized, double-masked, group-comparison, phase 1 clinical study.In the initial singleinstillation trial, 45 healthy volunteers were randomly subdivided into 5 groups and treated with SNJ-1656 in concentrations of 0.003%, 0.01%, 0.03%, 0.05%, and 0.1% in stepwise fashion.In the repeated-instillation trial, 36 healthy volunteers were assigned to receive SNJ-1656 ophthalmic solution at the following concentrations and dosages: 0.05% once daily, 0.1% once daily, 0.05% twice daily, or 0.1% twice daily.In our studies, the administration of the solution and subsequent examinations (including intraocular pressure IOP measurements) were performed in a double-masked fashion.Results: After single instillation of placebo or SNJ-1656, in concentrations of 0.003%, 0.01%, 0.03%, 0.05%, and 0.1%, the changes in IOP from the baseline were -0.91, -1.18, -1.48, -2.20 (P = .04vs placebo), -1.48, and -1.98 mm Hg, respectively, at 2 hours, and -0.63,-0.95,-1.79, -2.26 (P = .01vs placebo), -1.95, and -3.00 mm Hg (PϽ .001vs placebo) respectively, at 4 hours.Significant IOP reductions after repeated instillation were also found.On slitlamp examination during the trial, there were no significant adverse findings except hyperemia of the bulbar and palpebral conjunctiva after instillation. Conclusion:This clinical study demonstrated that SNJ-1656 is a safe topical agent effective in reducing IOP in human eyes.