Immediate Allogeneic Hematopoietic Cell Transplantation (HCT) in Acute Myeloid Leukemia (AML) Arising From Myelodysplastic Syndrome (MDS)
Authors: Kim Sung-Doo , Choi Yunsuk , Park Young-Hun , Lee Jae Seok , Kim Dae-Young , Lee Jung-Hee , Lee Kyoo-Hyung , Seol Miee , Lee Young-Shin , Kang Young-Ah , Jeon Mijin , Jung Ah Rang , Lee Je-Hwan 
Published: October 2019

Abstract
Abstract 2031

Introduction:
Treatment of secondary AML arising from MDS is unsatisfactory. Induction rate of complete remission (CR) is low with standard inuction chemotherapy regimen and relapse is common without allogeneic HCT. Immediate allogeneic HCT without induction chemotherapy can be an option if an appropriate donor is available in patients whose disease progress into AML from MDS. We intended to analyze the benefit of immediate allogeneic HCT versus induction chemotherapy in patients with AML arising from MDS.

Methods:
Between 1991 and 2010, 95 patients were diagnosed with AML that had evolved from antecedent MDS. After the diagnosis of AML, 10 patients received supportive care only. This retrospective study involved analysis of data from remaining 85 patients; 11 proceeded to immediate allogeneic HCT without induction chemotherapy (HCT group) and 74 were treated with induction chemotherapy (IC group). The clinical outcomes between the HCT group and the IC group were compared.

Results:
Median age was 48 years (range, 18–78). Patient characteristics at the time of AML diagnosis were similar between the HCT and IC groups except total leukocyte counts, which were higher in the IC group than the HCT group (P=0.009). Patients in the IC group were initially treated with induction chemotherapy consisted mostly of cytarabine plus daunorubicin or idarubicin, while those in the HCT group received allogeneic HCT from HLA matched sibling donors (n=7) or unrelated volunteers (n=4). Thirty-one patients (41.9%) in the IC group achieved CR with induction chemotherapy, whereas 9 (81.8%) in the HCT group achieved CR after HCT (P=0.013). Of 74 patients in IC group, 28 underwent allogeneic HCT in their disease status of the first CR (n=13), primary refractory disease (n=10), or the first or second relapse (n=5). The median follow-up duration for surviving patients was 8.2 months (range, 0.2–171.3). During this time, 62 patients died, 16 relapsed after CR, and 68 died or relapse. The median overall survival (OS) and event-free survival (EFS) were 8.3 and 6.4 months, respectively. Relapse probability at 5 years was 49.2%. The HCT group showed a significantly longer EFS than did the IC group (median 29.2 vs. 5.2 months, P=0.042). OS of the HCT group was higher than that of the IC group, but the difference was not statistically significant (median 34.6 vs. 7.6 months, P=0.149). Relapse probability was not significantly different between the two groups (35.7% vs. 53.1% at 5 years, P=0.278). After adjustment for other variables, the HCT group showed significantly better outcomes than did the IC group in terms of CR rate (HR, 11.195; 95% CI, 1.940–64.619; P=0.007) and EFS (HR, 0.384; 95% CI, 0.163–0.905; P=0.029).

Conclusions:
Immediate allogeneic HCT is a viable option in AML arising from MDS if an appropriate donor is available.

Disclosures:
No relevant conflicts of interest to declare.