Administration of human recombinant granulocyte colony-stimulating factor (filgrastim) accelerates granulocyte recovery following high-dose chemotherapy and autologous marrow transplantation with 4-hydroperoxycyclophosphamide-purged marrow in women with metastatic breast cancer.

Stem cell contamination by tumor is common in many diseases for which autologous bone marrow transplantation is used. In in vitro models chemotherapeutic purging reduces contamination and may have an impact on clinical outcome. Purging, however, delays engraftment. Little is known about the ability of granulocyte colony-stimulating factor (G-CSF) to accelerate myelopoiesis after purged autologous bone marrow transplantation. We treated 22 women with metastatic breast cancer with high-dose cyclophosphamide and thiotepa and, following the infusion of 4-hydroperoxycyclophosphamide-purged marrow, administered G-CSF, 16 micrograms/kg daily, from day 0 to engraftment. Results were compared with a control population of 24 women with breast cancer who received identical chemotherapy and purged marrow but not growth factor. Neutrophil recovery was accelerated in the G-CSF-treated population. An absolute neutrophil count of 500 was reached in 19 days compared with 29 for the historic controls. The median number of days febrile was reduced (8 versus 5.5) as were the number of days of hospitalization from marrow infusion (33 versus 25). There was no difference in the number of days on antibiotics or time to last platelet transfusion. G-CSF was administered without any notable toxicity. G-CSF accelerates myelopoiesis following the infusion of 4-hydroperoxycyclophosphamide-purged autologous marrow and shortens hospitalization.