C-KIT- Mutated t(8;21)AML Patients with >3log Reduction of MRD Conferred a Very High Relapse and Need HSCT to Improve Outcome

Abstract

[Objective] Previous studies showed that c-KIT mutation and <3log reduction of minimal residual disease (MRD) were two poor prognostic markers for acute myeloid leukemia (AML) with t(8;21) . However, How to deal with c-KIT- mutated t(8;21)AML patients with >3log reduction of MRD remains undefined. To answer this question, we performed this study.[Methods] The current retrospective study consisted of 70 newly diagnosed patients with c-KIT- mutated t(8;21)AML during July 2005 and March 2016 in Peking University People's Hospital. Induction treatment included standard 3+7' regimen or HAA regimen. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) was recommended to all patients with an available donor after 2-3 cycles of consolidation treatment with high-dose cytarabine(HDAC). Patients without a donor or refusing HSCT received HDAC-based intensive treatment. MRD was determined by RUNX1/RUNX1T1 transcript levels detected by Q-PCR. The last follow-up time was July 2016.[Results] Sixty-nine out of 70 patients achieved complete remission(CR).Two patients relapsed after first cycle of consolidation treatment. There were 60 patients having the results of MRD after 2 cycles of consolidation treatment (Figure 1). Thirty-four patients achieved >3log reduction of RUNX1/RUNX1T1 transcript levels (defined as major molecular remission, MMR). There were 16 and 18 patients finally receiving chemotherapy and allo-HSCT. Twenty-six patients did not achieve MMR, and 12 and 14 patients finally receiving chemotherapy and allo-HSCH, respectively. For patients achieving MMR, the 4-year cumulative incidence of relapse (CIR) and disease-free survival (DFS) were 84.8% vs.6.7% (p<0.001) and 20.6% vs.87.5% (p<0.001) when receiving chemotherapy or allo-HSCT(Figure 2). For patients not achieving MMR, the 4-year CIR and DFS were 100% vs.30.8% (p<0.001) and 0% vs.60% (p<0.001) when receiving chemotherapy or allo-HSCT (Figure 2). Multivariate analysis revealed that MRD status (MMR or non-MMR and treatment choice (HSCT or chemotherapy) were independent prognostic factors for relapse, DFS.[Conclusion] We concluded that c-KIT- mutated t(8;21)AML patients with >3log reduction of MRD conferred a very high relapse and need allo-HSCT to improve outcome. [Display omitted] [Display omitted] [Display omitted] DisclosuresNo relevant conflicts of interest to declare.