Hematopoietic growth factors.

Recent advances in our understanding of the hemolymphopoietic growth factors has revolutionized knowledge of blood cell development, the immune system, and of tumor cell biology. However, the rapid translation of these insights from basic research to the clinic has been perhaps the most dramatic part of the story. Commercially available erythropoietin has become established for the treatment of the anemia of end-stage renal disease, and promises to be of value in the supportive care of patients with cancer and perhaps other chronic diseases. It likely will be increasingly utilized for enhancing autologous blood donation and for perioperative management. Both GM-CSF and G-CSF only recently released by the FDA for specific clinical indications, though there are a variety of potential applications (Table 12). It is clear that G-CSF is the therapy of choice for most neutropenias and that both agents have effects in diminishing the myelotoxicity and mucositis seen after aggressive chemoradiotherapy. However, it is important to note that as yet there is no evidence that the use of either G-CSF or GM-CSF has resulted in increased cure rates or, in fact, increased survival in patients with various malignancies. It would appear that both G-CSF and GM-CSF will, in fact, allow dose escalation and/or diminished toxicity of various chemotherapeutic regimens. However, there are important considerations in the overall place of these cytokines with regard to treatment of human disease. A major goal in the therapy of patients with malignancy is obviously prolongation of life and cure. If, in fact, escalation of doses of chemotherapeutic agents does not result in increased tumor responses or cures then the use of these growth factors will have a relatively trivial impact on the care of cancer patients. In addition, the disturbing observations of receptors for these growth factors on various tumor cell lines and of varying degrees of in vitro tumor cell proliferative responses raises the possibility that in some situations they may actually stimulate tumor growth. This is an unknown which has not been adequately evaluated in any clinical study to date and which may vary from tumor to tumor. For example, if these cytokines increase tumor growth rate by 20-30% (an effect which would probably not be detected in the clinical studies to date) while allowing an escalation of chemotherapy doses it is possible that there would be no significant beneficial effect.(ABSTRACT TRUNCATED AT 400 WORDS)