GRANULOCYTE-COLONY-STIMULATING FACTOR GIVEN IN ADDITION TO INTERFERON-ALPHA TO MOBILIZE PERIPHERAL-BLOOD STEM-CELLS FOR AUTOLOGOUS TRANSPLANTATION IN CHRONIC MYELOID-LEUKEMIA

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 mu g/kg/d, was adminis tered subcutaneously together with IF-alpha to 30 CML patients in haem atological remission but with various degrees of cytogenetic remission , after IF-alpha therapy. Peripheral blood stem cells (PBSC) were harv ested 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 th e percentage of Ph+ cells in the bone marrow under G-CSF therapy The p ercentage of Ph+ cells in apheresis products tended to decrease betwee n the first and the last apheresis (P=0.05). 14 patients who were not responsive to IF-alpha were transplanted after conditioning with busul phan 16 mg/kg and melphalan 140 mg/m(2). 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 graf t (P = 0.02). We conclude that this procedure is feasible, allowing th e harvest of enough PBSC, some of them Ph- in patients who responded t o IF-alpha, to allow autologous transplantation.