Recombinant adeno-associated virus encoding the monhematocrits reached 62 and 75% by week 10 (from prekey erythropoietin gene (rAAV-cm-Epo) was generated injection values of 38 and 40%, respectively) and remained and tested for its potential to confer long-term expression elevated throughout the study period (28 weeks). Circulatof the gene product following intramuscular injection. A ing Epo levels were also elevated throughout the study persingle intramuscular injection of 2 × 10 12 rAAV-cm-Epo pariod. Our data demonstrate the potential for long-term gene ticles into two baboons led to sustained high circulating expression in large animals by a single intramuscular injecEpo levels and a concomitant increase in hematocrit. The tion of a recombinant adeno-associated virus (rAAV) vector.