The administration of 10 mu g/kg granulocyte colony-stimulating factor (G-CSF) alone results in a successful peripheral blood stem cell collection when previous mobilization with chemotherapy and hematopoietic growth factor failed

Some heavily pretreated cancer patients fail to mobilize enough peripheral blood stem cells (PBSC) after stimulation with chemotherapy and hematopoiet ic growth factors. For these patients the best way to obtain an adequate PB SC collection is unknown. Here we report 6 heavily pretreated cancer patien ts who failed to mobilize sufficient PBSC after stimulation with chemothera py and G-CSF 5 mu g/kg/day. In these cases, we used G-CSF 10 mu g/kg/day al one for six days at least 3 weeks after the last chemotherapy. After three consecutive leukaphereses starting on day 5, five patients had adequate PBS C collections. With 6 days of G-CSF 10 mu g/kg/day alone, 2.8 x 10(6) (+/- 1) CD34(+) cells/kg were collected. This was significantly higher than the number of CD34(+) cells/kg collected after chemotherapy and G-CSF 5 mu g/kg 0.3 x 10(6) (+/- 0.1) [P=0.05]. Four patients received high-dose chemother apy with PBSC support. Hematologic recovery observed in these patients was as expected. In conclusion, G-CSF 10 mu g/kg alone can mobilize progenitor cells into peripheral blood when previous mobilization with chemotherapy an d C-CSF 5 mu g/kg fails.