Hematopoietic effects and clinical uses of granulocyte-macrophage colony-stimulating factor and PIXY321

The clinical uses of granulocyte-macrophage colony-stimulating factor (GM-CSF) are expanding. GM-CSF was originally approved for use after autologous bone marrow transplantation. More recent phase III studies using GM-CSF after allogenic marrow transplantation show a similar reduction in the duration of neutropenia and monocytopenia. In phase III trials following standard-dose chemotherapy, GM-CSF significantly reduced treatment-related neutropenia and morbidity and, in one study, mortality. Nonrandomized studies using GM-CSF prior to and during chemotherapy for acute myeloid leukemia to improve remission rates have not demonstrated an obviously significant benefit. Other studies of GM-CSF to augment cancer therapies directly and to aid in the treatment of infection are in progress. PIXY321 is a fusion protein of GM-CSF and interleukin-3. PIXY321 was developed, in part, because in vitro and in vivo laboratory studies suggested synergy between its two components. Phase I-II clinical studies using PIXY321 are preliminary but show encouraging results with stimulation of multilineage hematopoiesis.