Prognostic impact of number of induction courses to attain complete remission in acute myeloid leukemia

For the majority of patients with acute myeloid leukemia (AML) an allogeneic stem cell transplant (SCT) in first complete remission (CR) is preferred. Whether the number of induction courses required to achieve CR has a prognostic impact is unclear. A retrospective study by the European Society for Blood and Marrow Transplantation included 4995 AML patients undergoing SCT from either a fully matched sibling or a 10/10 or 9/10 HLA-matched unrelated donor. Among these patients 77% had achieved CR after one induction course, while 23% had needed two induction courses. The latter group had worse relapse incidence, leukemia-free survival, and overall survival but not nonrelapse mortality when compared to the group who achieved CR after only one induction course. In multivariate analysis, needing two induction course to achieve CR was also associated with increased risk of relapse (HR 1.38; p=0.0003) and death (1.27; p=0.002). The authors conclude that initial response to chemotherapy as determined by the number of courses to attain CR, retained prognostic relevance even following SCT in CR.