Treatment of relapsed acute myeloid leukemia using GM-CSF before intensive chemotherapy

Ten patients with acute myeloblastic leukemia (AML) in first relapse were treated with high-dose cytosine-arabinoside (ara-C, 3 g/m2/12 hours x 4) and amsacrine (150 mg/m2/day x 5). In order to prime the cells, the patients were given rh-GM-CSF (3 micrograms/kg/d) for four days, the first infusion starting 48 hours before chemotherapy. Two patients died during the aplastic phase, seven patients achieved a second complete remission (CR2) and one patient remained leukemic. The median duration of aplasia was 17 days (14-21). These results were comparable to those obtained in our previous series of 27 patients treated for AML in first relapse with the same chemotherapy but without GM-CSF (66% CR2). After 48 hours of GM-CSF infusion, (before chemotherapy was started), seven patients had an increase in the white blood cell count with an increase in the absolute number of blast cells in five of these cases. Marrow blast cells percentages increased in 3 of the 8 patients analysed. Six of seven patients tested showed an increase in the percentage of cells in S-phase (studied by flow cytometry using the bromodeoxyuridine (BrdU/DNA) labelling technique and BrdU incorporation). GM-CSF used to prime leukemic cells may be safely administered but its clinical usefulness needs to be further evaluated.