PRECIS: In pooled phase III analyses, once-daily netarsudil 0.02% resulted in intraocular pressure (IOP) reduction that was noninferior to twice-daily timolol 0.5%, with minimal treatment-related serious or systemic adverse events (AEs). Ocular AEs were generally tolerable. PURPOSE: The purpose of this study was to assess the efficacy and safety of the Rho kinase inhibitor netarsudil in patients with open-angle glaucoma or ocular hypertension. PATIENTS AND METHODS: Pooled analysis of data from the ROCKET-1 to 4 phase III studies of once-daily (PM) netarsudil or twice-daily timolol in patients with open-angle glaucoma or ocular hypertension. The primary efficacy measure was mean IOP at 8:00 AM, 10:00 AM, and 4:00 PM at week 2, week 6, and month 3 in patients with baseline IOP <25 mm Hg. RESULTS: In the pooled primary efficacy population (netarsudil, n=494; timolol, n=510), once-daily netarsudil was noninferior to twice-daily timolol at all 9 timepoints through month 3. Mean treated IOP ranged from 16.4 to 18.1 mm Hg among netarsudil-treated patients and 16.8 to 17.6 mm Hg among timolol-treated patients. In the pooled safety population (n=839 in each treatment group), treatment-related serious AEs occurred at similar frequencies in each treatment group (netarsudil, 0.1%; timolol, 0%). The most common ocular AE, conjunctival hyperemia (netarsudil, 54.4%; timolol, 10.4%), was graded as mild in 77.6% (354/456) of affected netarsudil-treated patients. CONCLUSIONS: Once-daily netarsudil resulted in IOP lowering that was noninferior to twice-daily timolol, with tolerable ocular AEs that were generally mild and self-resolving. As a first-in-class agent in the United States, with a novel mechanism of action, netarsudil may provide a useful therapeutic option for patients who would benefit from IOP lowering.