We investigated the assessment of blood flow within polypoidal lesions using optical coherence tomography angiography (OCTA) to determine intravitreal brolucizumab (IVBr) efficacy for treating polypoidal choroidal vasculopathy (PCV). We retrospectively studied 46 eyes with PCV that completed 1-year IVBr treatment. Blood flow signals within polypoidal lesions were evaluated using OCTA after loading-phase treatment, and 1-year outcomes were compared between eyes in which blood flow signals disappeared versus persisting. After loading-phase treatment, blood flow signals within polypoidal lesions disappeared in 31 eyes and persisted in 15. In the former group, visual acuity improved significantly throughout the year (P < 0.01), while in the latter there was no significant difference between baseline and after 1 year. The total number of injections was significantly lower with than without disappearance of blood flow signals (6.0 vs. 6.9, P < 0.01). The intended injection interval at the last visit was significantly longer in the former than in the latter group (15.7 weeks vs. 12.5 weeks, P < 0.01). These results indicate that PCV cases showing disappearance of blood flow signals within polypoidal lesions by OCTA after loading-phase treatment had favorable 1-year outcomes of IVBr. Therefore, evaluating blood flow within polypoidal lesions by OCTA may allow noninvasive prediction of PCV treatment outcomes.