The clinical trial incorporates a Phase II component that will evaluate the efficacy of Rexin-G using an adaptive trial design. Each treatment cycle will be six weeks: four weeks of treatment and two weeks of rest. Unlike a standard Phase I protocol, eligible patients may have repeat cycles after the safety data and objective tumor response/s are recorded. Continued Rexin-G treatment will enable the targeted nanomedicine to catch up with tumor growth, halt disease progression, and reduce tumor burden. The treatment strategy is to achieve tumor control as quickly as safely possible. 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 for breast cancer.