ABSTRACT: To determine safety and efficacy of intravitreal high-dose ranibizumab in the treatment of active neovascular polypoidal choroidal vasculopathy (PCV).In this Phase I/II, single-center, randomized, controlled, double-masked study, predominantly non-Asian, previously treated or treatment-naive, male and female adult patients were randomized to receive high-dose (1.0/0.1 ml or 2.0 mg/0.05 ml; n=15) or standard-dose (0.5 mg/0.05 ml; n=5) ranibizumab in 3 monthly loading doses, followed by 9 months of criteria-based, as-needed retreatment. Safety was evaluated by a descriptive analysis of all non-serious and serious adverse events, angiographic assessments, physical examinations, vital signs, ocular examinations, and visual acuity measurements. Visual acuity and anatomic outcomes are described for the high-dose group.Twenty patients (aged 35-76 years; 8 Black, 11 White, 1 Asian) were enrolled. At baseline, in the high-dose group, mean best-corrected visual acuity (BCVA) was 63.5 letters (Snellen equivalent ~20/50), and mean baseline central foveal thickness (CFT) was 253.7 ?m. High-dose ranibizumab was generally well tolerated without evidence of ocular or systemic severe adverse events, including arterial thromboembolic events. At month 12, in the high-dose group, the mean overall change from baseline in BCVA was +6.7 letters and in CFT was -49.7 ?m.High-dose ranibizumab monotherapy is safe and efficacious for treating patients with PCV.