VHL and renal cell carcinoma: One patient with refractory retinal hemangioblastomas had a marked improvement in visual acuity after 7 months’ semaxinib treatment [7], another with RCC likely due to VHL had a complete metabolic and radiological response that persisted for 18 months after treatment [8], and a the response rate in a small clinical trial (n=6) was 33% [9].