Blood Res.  2020 Dec;55(4):217-224. 10.5045/br.2020.2020127.

Outcomes of pediatric acute myeloid leukemia patients with FLT3-ITD mutations in the pre-FLT3 inhibitor era

• Choi S
• Kim BK
• Ahn HY
• Hong KT
• Choi JY
• Shin HY
• Kang HJ

• KMID: 2509961
• DOI: http://doi.org/10.5045/br.2020.2020127

Abstract

Background
Acute myeloid leukemia (AML) with internal tandem duplication in FMS-like tyrosine kinase 3 (FLT3-ITD) is associated with poor outcomes. This study aimed to analyze the outcomes of pediatric AML patients with FLT3-ITD mutations in the pre-FLT3 inhibitor era.
Methods
We retrospectively reviewed and identified 18 patients diagnosed with non-M3 AML with FLT3-ITD mutations at Seoul National University Children’s Hospital between May 2008 and August 2019.
Results
The median age was 13 years (range, 6‒19 yr). The median follow-up time was 43 months (range, 6‒157 mo). Fourteen patients received BH-AC-based (N4-Behenoy1-1-β-D-arabinofuranosy1cytosine) and 4 received cytarabine-based induction chemotherapy. Complete remission (CR) was achieved in 72.2% of the patients after the first induction chemotherapy and 80% of the patients achieved CR after salvage therapy. The overall CR rate was 94% (17/18 patients). These 17 patients underwent hematopoietic stem cell transplantation (9 matched unrelated donors, 5 matched related donors, and 3 haploidentical donors). Relapse occurred in 22% of the patients. Event free survival and overall survival rates were 53.8±12.1% and 53.6±12.1%, respectively, and they were not significantly different according to the type of induction chemotherapy (P=0.690) or the type of donor (P =0.102).
Conclusion
This study outlines the outcomes of pediatric AML patients with FLT3-ITD-mutations in one institution over a decade. Outcomes were significantly improved in this study compared to our previous report in 2004, where RFS and EFS were 0%. This study can provide baseline data for pediatric patients in the pre-FLT3 inhibitor era.

Keyword

FLT3-ITD; Acute myeloid leukemia; Pediatric; Overall survival

Figure

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  Fig. 1 Treatment and outcome of patients. a)Enocitabine, idarubicin, intrathecal cytarabine; b)cytarabine, idarubicin, mitoxantrone.Abbreviations: AML, acute myeloid leukemia; CR, complete remission; DOD, died of disease; HSCT, hematopoietic stem cell transplant; MRD, matched related donor; MUD, matched unrelated donor; N, number; NED, no evidence of disease; TRM, treatment-related mortality.

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  Fig. 2 Patients’ overall survival (OS) and event free survival (EFS). Abbreviations: Haplo, haploidentical; HSCT, hematopoietic stem cell transplant; MRD, matched related donor; MUD, matched unrelated donor.

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