ADMINISTRATION OF HUMAN RECOMBINANT GRANULOCYTE-COLONY-STIMULATING FACTOR (FILGRASTIM) ACCELERATES GRANULOCYTE RECOVERY FOLLOWING HIGH-DOSECHEMOTHERAPY 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 che motherapeutic purging reduces contamination and may have an impact on clinical outcome. Purging, however, delays engraftment. Little is know n about the ability of granulocyte colony-stimulating factor (G-CSF) t o accelerate myelopoiesis after purged autologous bone marrow transpla ntation. We treated 22 women with metastatic breast cancer with high-d ose cyclophosphamide and thiotepa and, following the infusion of 4-hyd roperoxycyclophosphamide-purged marrow, administered G-CSF, 16 mug/kg daily, from day 0 to engraftment. Results were compared with a control population of 24 women with breast cancer who received identical chem otherapy and purged marrow but no growth factor. Neutrophil recovery w as 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 antibi otics or time to last platelet transfusion. G-CSF was administered wit hout any notable toxicity. G-CSF accelerates myelopoiesis following th e infusion of 4-hydroperoxycyclophosphamide-purged autologous marrow a nd shortens hospitalization.