Rexin-G is a tumor-targeted (pathotropic or disease-seeking) nanoparticle that when injected intravenously, seeks out and accumulates in cancerous lesions, thus enhancing local drug concentration within tumors. The goal of the adaptive trial design is to confirm the over-all safety of Rexin-G and to determine the optimal dosing regimen for Rexin-G that would document the significant clinical benefits required to support a Phase II registration protocol.