Peripheral blood stem cell transplantation as an alternative to autologous marrow transplantation in the treatment of acute myeloid leukemia?

Abstract

The clinical use of autologous marrow transplantation in acute myeloid leukemia (AML) has been hampered by the inability to collect adequate numbers of cells after remission induction chemotherapy and the notably delayed hematopoietic regeneration following autograft reinfusion. Here we present a study in which the feasibility of mobilizing stem cells was investigated in newly diagnosed AML. Among 96 AML patients, 76 patients (79%) entered complete remission. Mobilization was undertaken with low dose and high dose schedules of G-CSF in 63 patients, and 54 patients (87%) were leukapheresed. A median of 2.0 × 10⁶ CD34⁺cells/kg (range 0.1–72.0) was obtained in a median of three leukaphereses following a low dose G-CSF schedule (150 μg/m²) during an average of 20 days. Higher dose regimens of G-CSF (450 μg/m² and 600 μg/m²) given during an average of 11 days resulted in 28 patients in a yield of 3.6 × 10⁶ CD34⁺ cells/kg (range 0–60.3) also obtained following three leukaphereses. The low dose and high dose schedules of G-CSF permitted the collection of 2 × 10⁶ CD34-positive cells in 46% and 79% of cases respectively (P = 0.01). Twenty-eight patients were transplanted with a peripheral blood stem cell (PBSC) graft and hemopoietic repopulation was compared with the results of a previous study with autologous bone marrow. Recovery of granulocytes (>0.5 × 10⁹/l, 17 vs 37 days) and platelets (>20 × 10⁹/l; 26 vs 96 days) was significantly faster after peripheral stem cell transplantation compared to autologous bone marrow transplantation. These results demonstrate the feasibility of PBSCT in the majority of cases with AML and the potential advantage of this approach with respect to hemopoietic recovery.