Colony-stimulating factors. Present status and future potential.

Granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) have been used successfully to enhance neutrophil recovery in patients with various malignancies undergoing standard or high dose chemotherapy, with or without autologous or allogeneic bone marrow transplantation support, and offer potential advantages in these settings in terms of reducing the total costs of healthcare and/or improving therapeutic outcomes. Clinical trials are now aimed at identifying which patients and which nonhaematological malignancies will respond best to colony-stimulating factor (CSF) support, and which of the 2 factors is the most appropriate in each setting. Two areas of considerable interest at present are the potential for chemotherapy dose optimisation and intensification with CSF therapy, and the use of CSFs to permit the harvest and reinfusion of peripheral blood progenitor cells as an alternative to autologous or allogeneic bone marrow transplantation. In the case of dose-intensified chemotherapy, costs of treatment increase but the gain may be an increase in survival rates or disease-free intervals. The potential of G-CSF and GM-CSF therapy in other conditions, notably haematological malignancies such as myelodysplasia and myeloid leukaemias, and AIDS, means that these agents are likely to make a significant impact on the treatment of a wide range of debilitating conditions in the future.