Mobilization of peripheral blood progenitor cells by hematopoietic growth factors.

The anti-tumor effect and toxicity of chemotherapeutic agents are dose-related. The dose-response curve for these agents is sigmoidal with a threshold, a lag phase, a linear phase and a plateau phase. The aim of cancer chemotherapy is to exploit the difference between the response curves for the tumor and normal tissues. In the laboratory and in some animal models, the dose-response curve for many agents demonstrates a log-linear relationship between dose and cell kill so that a doubling of the drug dose may increase cell kill by ten-fold. The more effective a drug is, the steeper the dose-response curve. Dose may be an important variable in the outcome of therapy, however, this dose-response relationship has been difficult to demonstrate because a dose-response effect may not be evident for most human tumors in the dose ranges used in clinical trials.