The impact of FLT3 mutations on treatment response and survival in Chinese de novo AML patients

The effect of haploidentical hematopoietic stem cell transplantation on comutations based on next-generation sequencing in adult acute myeloid leukemia patients with the FLT3-ITD mutation

According to the 2022 European LeukemiaNet, all acute myeloid leukemia (AML) cases with FLT3-ITD mutations are now categorized as intermediate risk irrespective of the FLT3-ITD allelic ratio or concurrent presence of NPM1 mutation. However, whether other next-generation sequencing (NGS) comutation genes can add layers to FLT3-ITD and whether the poor outcomes of FLT3-ITD comutations can be overcome by haploidentical hematopoietic stem cell transplantation (haplo-HSCT) are unclear. This study aimed to investigate which comutations based on NGS at diagnosis affect the clinical prognosis of de novo AML patients with FLT3-ITD mutations and the effect of haplo-HSCT on comutations. We analyzed 95 de novo AML patients with FLT3-ITD mutations from January 2018 to August 2021 based on the NGS 99-gene platform. Forty-one other types of molecular mutations were detected. The most common cooccurring mutations were NPM1 (n = 43, 45.3%) and DNMT3A (n = 21, 22.1%). NPM1 mutation did not affect the clinical outcomes. Acute myeloid leukemia patients with FLT3-ITD and DNMT3A comutations had significantly worse 3-year Disease-free survival (DFS) (49.5% vs. 69.3%, P = 0.01) and Overall survival (OS) rates (61.1% vs. 69.8%, P = 0.54) than those without DNMT3A mutations, and survival was significantly more favorable after haplo-HSCT than that after chemotherapy (3-year DFS, 85.7% vs. 30.8%, P = 0.006; 3-year OS, 85.7% vs. 43.1%, p = 0.08). In multivariate analysis, DNMT3A mutation was a risk factor for DFS, while haplo-HSCT was a protective factor. In conclusion, DNMT3A mutation might be a poor prognostic factor in adult AML patients with FLT3-ITD mutations, and haplo-HSCT could overcome the poor prognosis of DNMT3A comutation.

GSK3 inhibitor suppresses cell growth and metabolic process in FLT3-ITD leukemia cells

Glycogen Synthase Kinase-3 (GSK-3) was recently implicated in the dysregulated biology of acute myeloid leukemia (AML). Low concentrations of GSK-3 inhibitors, SB216763 and BIO, suppressed the proliferation of AML cells with FLT3-ITD as early as 24 h after treatment. BIO was used in subsequent assays since it exhibited higher inhibitory effects than SB216763. BIO-induced G1 cell cycle arrest by regulating the expression of cyclin D2 and p21 in MV4-11 cells, and promoted apoptosis by regulating the cleaved-caspase3 signaling pathways. In vivo assays demonstrated that BIO suppressed tumor growth, while metabolomics assay showed that BIO reduced the levels of ATP and pyruvate in MV4-11 cells suggesting that it inhibited glycolysis. BIO markedly suppressed cell growth and induced apoptosis of AML cells with FLT3-ITD by partially inhibiting glycolysis, suggesting that BIO may be a promising therapeutic candidate for AML.

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

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-b-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.

The Role of FLT3-ITD Mutation on de Novo MDS in Chinese Population

BACKGROUND

FLT3 mutations have been well-studied in acute myeloid leukemia (AML), and the detection of the FLT3 gene has become a clinical routine. However, it has not been fully analyzed in other hematologic malignancies, such as myelodysplastic syndromes (MDS).

MATERIALS AND METHODS

Between 2010 and 2016, 304 adult patients with de novo MDS had the FLT3 sequence tested on their bone marrow sample. With 279 patients who had follow-up information, we also analyzed the impact of clinical and laboratory characteristics as well as FLT3 mutation status and treatment on prognosis.

RESULTS

We found that the transformation rate was 3 (42.9%) of 7 patients in the FLT3-ITD-positive group, compared with 31 (10.4%) of 297 among FLT3-ITD-negative patients (P = .033). The median progression-free survival of the FLT3-ITD mutated and wild-type groups were 43 days and 363.5 days, respectively (P < .0001). The median overall survival (OS) of the 2 groups were 218 days and 410.5 days, respectively (P < .0001). We also found that 5 factors had independent prognostic impact on OS: white blood cell counts, bone marrow blast percentage, cytogenetics, transplantation status, and FLT3-ITD mutation. Furthermore, compared with the transformation group, the non-progression group was younger (P = .034), with a lower platelet count (P = .022), a lower bone marrow blast percentage (P = .001), a lower FLT3-ITD incidence (P = .007), and a longer OS (P < .0001).

CONCLUSIONS

When observed at the MDS stage, patients harboring FLT3-ITD mutations had higher AML transformation rate, quicker disease progression, and shorter survival than wild-type patients. Nevertheless, once the disease progressed to leukemia, the impact of FLT3-ITD mutations on prognosis was slight. In addition, the prognosis of secondary AML was very poor whether there was an FLT3-ITD mutation or not.