[Novel ways of using hemopoietic growth factors]

The myelopoietic growth factors, in particular G-CSF and GM-CSF have been available for clinical use for only a few years but they have already profoundly affected the management of chemotherapy-induced neutropenia, the use of dose-intensive chemotherapy regimens, and the practice and safety of autologous stem cell transplantation. While these growth factors have rapidly been introduced as routine agents in the management of cancer patients, they have continued to generate a considerable amount of basic research on the biology of hematopoiesis as well as on the growth regulation of normal and tumor cells. One attractive possibility offered by growth factors is to protect hemopoietic stem and progenitor cells from the toxic effects of chemotherapy, while not diminishing its anti-tumor action. Any means of preferentially and reversibly suppressing the proliferation of normal hemopoietic stem and progenitor cell while leaving unmodified the proliferation of tumor cells and their susceptibility to chemotherapy, could potentially optimize treatment efficacy. In the present paper, we have briefly discussed the possibility to use the myeloid growth factors as myeloprotective agents in the context of drug-intensified chemotherapy on the basis of the results obtained during some clinical trials recently conducted in patients with advanced cancer.