Feasibility and efficacy of salvage allogeneic stem cell transplantation in AML patients relapsing after autologous stem cell transplantation

Autologous hematopoietic cell transplantation (HCT) is suitable for consolidation of favorable-/intermediate-risk AML patients in CR1. However, ~50% of AML patients relapse after autologous HCT, and efficacy of subsequent salvage strategies including allogeneic HCT remains unclear. We studied 123 consecutive patients with newly diagnosed AML undergoing high-dose chemotherapy (HDCT)/autologous HCT in CR1. In relapsing patients afterwards, we analyzed salvage treatments and outcomes focusing particularly on salvage allogeneic HCT. Of 123 patients, 64 (52%) relapsed after autologous HCT. Subsequently, 13 (21%) received palliative therapy, whereas 51 (79%) proceeded to salvage therapy with a curative intent. Of the 47 patients with a curative intent and who did not proceed directly to allogeneic HCT, 23 (49%) achieved CR2 or had ongoing hematologic CR1 despite molecular relapse. Finally, 30 patients (47%) received allogeneic HCT with estimated 3-year leukemia-free and overall survival rates of 33% and 43%. Hematologic remission at allogeneic HCT and lack of acute GvHD had a positive impact on OS and LFS (p < 0.05). Our study suggests that almost 80% of AML patients can undergo salvage therapy following relapse after front-line HDCT/autologous HCT. Allogeneic HCT can provide cure in one third of patients relapsing after front-line HDCT/autologous HCT.