Outcome of allogeneic hematopoietic stem cell transplantation for relapsed/refractory acute myeloid leukemia in NR status

Abstract

Objective To explore the outcome of allogeneic hematopoietic stem cell transplantation (allo-HSCT) for relapsed/refractory acute myeloid leukemia (AML) patients in non-remission (NR) status and its related risk factors. Methods Thirty-nine relapsed/refractory AML patients in NR status who received allo-HSCT between Jan. 2006 and Dec. 2016 were retrospectively analyzed. Major end points of study included overall survival (OS), disease free survival (DFS), and relapse rate. Results All patients achieved hematopoietic reconstitution. Median time to neutrophil and platelet engraftment was 13 (11-20) and 16 (10-58) days, respectively. Acute graft-versus-host disease (aGVHD) occurred in 25 (64.1%) patients, and 11 (31.4%) patients developed chronic GVHD. During a median follow-up period of 9.1 (1.6-93.8) months, 11 (28.9%) cases survived, 10 (26.3%) survived without leukemia, and 21 (53.8%) relapsed. The estimated 2-year OS and DFS were 30.0%±8.0% and 26.7%±7.7%, and cumulative incidence of relapse and transplantation related mortality at 2 years was 56.63% (95% CI 37.84%-71.71%), 19.7% (95% CI 8.3%-34.5%), respectively. The multivariate analysis revealed that the number of bone marrow blasts≥25% or any level of blasts in peripheral blood was significantly associated with worse OS (HR=11.91, P=0.003), DFS (HR=10.75, P=0.002) and higher rate of relapse (70.83% versus 20.22%, P=0.002). In addition, the development of grade Ⅱ-Ⅳ aGVHD also predicted an inferior OS (HR=3.18, P=0.039). Conclusion Salvage therapy with allo-HSCT can induce long-term survival in part refractory/relapsed AML patients. Decrease in the pre-transplant disease burden is the key to reduce relapse and improve survival. Key words: refractory; relapse; acute myeloid leukemia; non-remission status; allogeneic hematopoietic stem cell transplantation