Allogeneic Stem-Cell Transplantation for Patients with De Novo Acute Myeloid Leukemia Not in Complete Response: Results of a Survey from the European Group for Blood and Bone Marrow Transplantation (EBMT).

Allogeneic stem-cell transplantation (alloSCT) is the most powerful antileukemic post-remission strategy in patients with acute myeloid leukemia (AML), and has shown its capability of increase leukemia-free survival and survival in earlier phases of the disease. However, the possible role of alloSCT in AML patients not in CR is mostly unknown, and deserves specific investigation. For this purpose, a survey within the EBMT registry including patients who underwent an undepleted alloSCT from an HLA-identical sibling for advanced AML (not in CR) was performed. We have analyzed 977 adults patients with AML submitted to alloSCT for a primary refractory disease (REF, n=346), first relapse (REL1, n=506) or second relapse (REL2, n=125) from 1990 to 2002 in EBMT centers. Median age was 40 (16 – 73) and 55% of patients were male. FAB classification was: M1/M2, 44%; M4/M5, 33%; M6, 5%; M0, 4%; M3, 3%; M7, 3%. Median time from diagnosis to alloSCT was 136, 219 and 403 days for REF, REL1, and REL2 subgroups, respectively. Bone marrow was the source of stem cells in a higher proportion of patients with relapsed disease as compared to refractory AML (59% for REL1 + REL2 vs 41% for REF, p<0001). Conditioning regimen included TBI in 56% of cases. No significant differences among subgroups (REF/REL1/REL2) were observed in terms of donor-recipient’s CMV status and TBI usage. After a median follow-up of 22 months, the main estimates of the outcome at 2 years are depicted in the following table:

In conclusion, although the overall outcome of HLA-identical sibling allotransplant for patients with non-CR AML is poor, a small fraction of patients, of approximately 20%, seems to benefit from the procedure in this otherwise incurable disease. A further analysis is addressed to the recognition of favorable prognostic factors in order to identify subgroups of patients with advanced AML who are candidates to allogeneic transplantation.