Autologous stem cell transplantation after complete remission and first consolidation in acute myeloid leukemia patients aged 61-70 years: results of the prospective EORTC-GIMEMA AML-13 study

Background and Objectives The optimal post-remission treatment for elderly patients with acute myeloid leukemia (AML) is presently unknown. Recent studies have reported the feasibility of autologous peripheral blood stem cell transplantation (PBSCT) in this population. We evaluate the outcome of this post-remission approach after complete remission (CR) and consolidation in elderly patients included in the EORTC - GIMEMA AML - 13 trial. Design and Methods PBSCT after induction and consolidation chemotherapy was evaluated in patients aged 61 to 70 years old with a WHO performance status 0-1. The induction therapy was mitoxantrone, etoposide and cytarabine (MICE) with or without granulocyte colony-stimulating factor (G-CSF) during and/or after chemotherapy. The consolidation therapy consisted of non-infusional or infusional idarubicin, etposide and cytarabine (mini-ICE). Results Sixty-one patients were scheduled for stem cell harvest by leukapheresis after s.c. recombinant human G-CSF administration initiated after hematopoietic recovery from consolidation. Stem cells were effectively harvested from 54 patients. A median of two aphereses (range, 1-5) were performed, resulting in a median collection of 11.7x10(8) nucleated cells/kg (range, 2.4-99.8) containing 40.2x10(4) CFU-GM/kg (range, 0-786.8), and 5x10(6) CD34(+) cells/kg (range, 0.1-99.8). For the whole group of 61 patients, the median disease-free survival (DFS) was 1.0 years and the 3-year DFS rate was 21%, while the median overall survival (OS) was 1.4 years and the 3-year OS rate was 32%. A total of 26 patients could not be autografed due to inadequate/no harvest (21 patients), early relapse (3 patients), or treatment refusal (2 patients). Autologous transplantation was performed in 35 patients following conditioning with the BAVC regimen. The median time for granulocyte recovery > 0.5x10(9)/L was 24 days and for platelets > 20x10(9)/L was 23 days following transplantation. After a median follow-up of 5.0 years from transplantation, the median DFS and OS were 1.1 and 1.6 years, respectively, and the 3-year rates were 28% and 39%, respectively. Eight autografted patients were still in continuous complete remission, 22 patients had relapsed and five had died in CR. Interpretation and Conclusions Intensification of remission treatment including autologous PBSCT was feasible in about half of harvested patients aged 61 to 70 years old, and did not improve the general outcome. This shows the limitations of autologous PBSCT and other intensive treatment modalities in elderly AML patients.