Allogeneic hematopoietic stem cell transplantation (HSCT) is increasingly used as an effective treatment for malignant disease. The three most common sources for stem cells used in HSCT are bone marrow (BM), umbilical cord blood (UCB), and peripheral blood stem cells (PBSC). In a retrospective review of 1,525 adults with acute leukemia receiving allogeneic transplants between 2002 and 2006, UCB accounted for 10.8%, PBSC for 58.2%, and BM for 31% of the population (Eapen et al., 2010). PBSC as a source of hematopoietic stem cells for transplantation has advantages over bone marrow in terms of donation ease and comfort and over cord blood in terms of adequate cell dose. However, PBSC transplantations are associated with an increased incidence of graft-versus-host disease (GVHD). Based on current literature acute GVHD (aGVHD) is reported in 48-80% of PBSCT recipients (Eapen et al., 2010, Ferrara et al., 2009). Additionally, the myeloablative conditioning regimens used for these transplants often result in mucositis which can be debilitating to patients. TXA127 is pharmaceutically-formulated angiotensin 1-7, a non-hypertensive derivative of angiotensin II. TXA127 has multilineage effects on hematopoietic progenitors in vitro and in vivo. The hematopoietic properties demonstrated in preclinical and clinical studies support the investigation of TXA127 to reduce the incidence of aGVHD and mucositis in this patient population.