Granulocyte colony‐stimulating factor given in addition to interferon‐α to mobilize peripheral blood stem cells for autologous transplantation in chronic myeloid leukaemia
In order to potentially mobilize and harvest the Ph cells observed in most patients with chronic myeloid leukaemia (CML) during interferon-alpha (IF-alpha) therapy, G-CSF (filgrastim), 5 microg/kg/d, was administered subcutaneously together with IF-alpha to 30 CML patients in haematological remission but with various degrees of cytogenetic remission, after IF-alpha therapy. Peripheral blood stem cells (PBSC) were harvested using standard aphereses from day 5 of G-CSF Patients underwent one to four (median three) aphereses. Median total yields/kg were 7.6 (range 3.8-25) x 10(8) MNC, 3.4 (0-140) x 10(6) CD34+ cells, and 17 (1.1-107) x 10(4) CFU-GM. No patient had a significant increase in the percentage of Ph+ cells in the bone marrow under G-CSF therapy. The percentage of Ph+ cells in apheresis products tended to decrease between the first and the last apheresis (P = 0.05). 14 patients who were not responsive to IF-alpha were transplanted after conditioning with busulphan 16 mg/kg and melphalan 140 mg/m2. Median time to neutrophils > 0.5 x 10(9)/l was 20 d (16-114 d) and to platelets > 50 x 10(9)/l 18 d (12-149 d). Nine patients had a major cytogenetic response post graft, which correlated with the amount of Ph+ cells reinfused with the graft (P = 0.02). We conclude that this procedure is feasible, allowing the harvest of enough PBSC, some of them Ph- in patients who responded to IF-alpha, to allow autologous transplantation.