Gene therapy holds promise for the treatment of both acquired and genetic disorders. Patients with diseases such as end-stage kidney disease, acquired immunodeficiency syndrome and cancer often develop anemia that can be treated by the frequent injection of recombinant human erythropoietin (EPO) protein. EPO delivery via gene therapy would provide a significant treatment benefit. EPO is normally expressed in the kidney, which is a poor target for gene therapy in most patients because of severe organ failure. Yet, serum proteins such as EPO can also be produced at ectopic sites and secreted to the serum. We have shown that delivering the EPO gene to skeletal muscle can alleviate anemia in an animal model. We also discovered that a novel method of a minimally invasive intravascular delivery of naked plasmid DNA, results in highly efficient transfection of skeletal muscle. This Phase II project will use this simple and safe gene delivery approach and will combine it with an innovative way to control EPO expression in order to develop a regulatable gene therapy protocol for the treatment of severe anemia.