Hematopoietic stem cell transplantation for de novo acute megakaryocytic leukemia in first complete remission: a retrospective study of the European Group for Blood and Marrow Transplantation (EBMT).

Acute megakaryoblastic leukemia (M7 AML) is a highly aggressive disease. We evaluated outcomes in 57 children (11 with Down syndrome) and 69 adults with M7 AML after first complete remission (CR1) following autologous or HLA-identical allogeneic transplantation. Characteristics of the recipients of autologous transplants (38 children, 37 adults) were, respectively: median age, 1.7 and 46 years; non-total body irradiation (non-TBI) conditioning regimen, 97% and 70%; bone marrow as stem cell source, 74% and 43%. Characteristics of the recipients of allogeneic transplants (19 children, 32 adults) were, respectively: median age, 2.8 and 37 years; non-TBI regimen, 63% and 42%; bone marrow as stem cell source, 95% and 69%. Autologous transplantation benefited children more; the relapse rate was high in adults. Results for autologous transplantation were (children and adults, respectively): engraftment, 90% and 100%; 3-year treatment-related mortality (TRM) rate, 3% and 8%; relapse rate, 45% and 64%; leukemia-free survival (LFS) rate, 52% and 27%; overall survival (OS) rate, 61% and 30%. After allogeneic transplantation, TRM was fairly low in children and adults, and relapse rates were lower than after autologous transplantation. Results for allogeneic transplantation were, respectively: engraftment, 95% and 90%; TRM, 0% and 26%; relapse rate, 34% and 28%; LFS, 66% and 46%; OS, 82% and 43%). We conclude that M7 AML patients in CR1 (except children with Down syndrome, who already have better outcomes) can benefit from transplantation.