Collection of Philadelphia-negative stem cells using recombinant human granulocyte colony-stimulating factor in chronic myeloid leukemia patients treated with alpha-interferon.

Autologous stem cell transplantation is a therapeutic option for chronic myeloid leukemia (CML) patients who are not candidates for allogeneic transplant. To reduce the risk of post-autografting disease recurrence, different strategies of stem cell selection have been attempted. The results of using recombinant human granulocyte colony-stimulating factor (rHuG-CSF) for harvesting hematopoietic progenitors in CML patients treated with interferon-a (IFN) are reported. Twenty-one CML patients who received IFN for a median of 21 (8-68) months were mobilized with rHuG-CSF (10 mg/kg/day). Twelve were in complete (CCR) or major (MCR) cytogenetic response. Complete success was considered a sufficient harvest (> 1 x 10(6)/kg CD34(+) cells/kg) without Philadelphia (Ph)+ metaphases in at least one apheresis; a partial success was a sufficient harvest with 1-35% Ph(+) cells. A total of 78 aphereses were performed. No patient had major side-effects. The median number (range) of mononuclear and CD34(+) cells obtained was, respectively, 8.6 x 10(8)/kg (0.9-22.6) and 3.3 x 10(6)/kg (0.4-26.3) per patient. A sufficient cell yield was collected in all but three patients. A complete/partial success was achieved in seven CCR/MCR patients (63%) and in three (33%) with other responses. Four patients underwent successful autografting using the stem cells obtained after rHuG-CSF mobilization. Mobilization of IFN-treated patients using rHuG-CSF is safe and provides a significant proportion of Ph-negative progenitors in CML patients in complete or major cytogenetic response.