Abstract: Objective To make a primary investigation of outcomes in relapsed or refractory (R/R) acute myeloid leukemia (AML) patients who were FLT3-ITD mutation negative and treated with sorafinib alone. Methods The clinical responses and survival of R/R AML patients who underwent sorafenib treatment only were retrospectively analyzed. The side effects and response results were assessed according to common terminology criteria for adverse events (CTCAE) v 4.0 from US National Institutes of Health and NCCN guideline. Results Four out of seven patients achieved complete remission by sorafenib treatment alone. The median time required for remission was 36 days in the four patients. Among them, only 1 patient stopped the maintenance treatment because of side effect of serious skin lesion. Three patients showed no response to sorafenib, including 2 accepted stem cell transplantation and 1 retrieved to salvage chemotherapy. All of them achieved complete remission later. One patient developed grade 1 adverse event of liver. Another one developed grade 3 skin lesion. All patients experienced neutropenia of more than 7 days without unendurable infections and early deaths. The median follow-up time for the whole cohort was more than 22 months. Three patients passed away for relapse of AML and their disease-free survival time with sorafenib ranged from 2 to 20 months. All four patients accepted stem cell transplantation were still surviving no matter whether or not they were responsive to sorafinib before. The median survival time for these seven patients was 650 days. Conclusion The R/R AML patients with negative FLT3-ITD mutation and high expression of CD117 treated with sorafenib alone have good remission and long term survival.

Key words: leukemia, myeloid, acute, relapsed/refractory, sorafenib, CD117 negative, FLT3-ITD mutation