Disclosed is a viral vector containing a nucleic acid sequence encoding erythropoietin (Epo), in operable linkage with an HRE expression control sequence, as well as uses of the vector; for instance, in preparing a medicament. Also provided are methods for treating anemia, can involve administering the vector to a patient, wherein expression of Epo is physiologically regulated such that hematocrit levels of the patient are corrected and maintained.