The myeloprotective effect of recombinant human granulocyte-macrophage colony-stimulating factor given sequentially with continuous infusion vinblastine in metastatic breast cancer patients.

Abstract

Colony-stimulating factors have been shown to have a myeloprotective effect when administered following chemotherapy. Chemotherapy of short duration with predominantly cell-cycle nonspecific agents has been most used. The myeloprotective effects of colony-stimulating factors given after cell-cycle specific or continuous infusion chemotherapy have not previously been assessed. Twenty-one evaluable patients with metastatic breast cancer progressing after one prior chemotherapy regimen were treated with continuous infusion vinblastine 2.0 mg/m2/day for 5 days. After the second chemotherapy cycle, granulocyte-macrophage colony-stimulating factor (GM-CSF) was given for 10 days. Serial complete blood counts, differential, and platelet counts were obtained to document myelotoxicity. GM-CSF administration resulted in a significantly shorter duration of granulocytopenia, < 500/microliters, at the maximum GM-CSF dose. Significantly more rapid recovery of granulocytes to > 500/microliters, > 1000/microliters, and > 1500/microliters was seen with all doses and schedules of GM-CSF administered. The nadir absolute granulocyte counts were unaffected. GM-CSF given after continuous infusion cell-cycle specific chemotherapy is therefore myeloprotective.