FLT3 mutated acute myeloid leukemia: 2021 treatment algorithm

Approximately 30% of patients with newly diagnosed acute myeloid leukemia (AML) harbor mutations in the fms-like tyrosine kinase 3 (FLT3) gene. While the adverse prognostic impact of FLT3-ITD^mut in AML has been clearly proven, the prognostic significance of FLT3-TKD^mut remains speculative. Current guidelines recommend rapid molecular testing for FLT3^mut at diagnosis and earlier incorporation of targeted agents to achieve deeper remissions and early consideration for allogeneic stem cell transplant (ASCT). Mounting evidence suggests that FLT3^mut can emerge at any timepoint in the disease spectrum emphasizing the need for repetitive mutational testing not only at diagnosis but also at each relapse. The approval of multi-kinase FLT3 inhibitor (FLT3i) midostaurin with induction therapy for newly diagnosed FLT3^mut AML, and a more specific, potent FLT3i, gilteritinib as monotherapy for relapsed/refractory (R/R) FLT3^mut AML have improved outcomes in patients with FLT3^mut AML. Nevertheless, the short duration of remission with single-agent FLT3i’s in R/R FLT3^mut AML in the absence of ASCT, limited options in patients refractory to gilteritinib therapy, and diverse primary and secondary mechanisms of resistance to different FLT3i’s remain ongoing challenges that compel the development and rapid implementation of multi-agent combinatorial or sequential therapies for FLT3^mut AML.Subject terms: Acute myeloid leukaemia, Targeted therapies     

Prognostic value of IDH1 mutations identified with PCR-RFLP assay in acute myeloid leukemia patients

BackgroundSomatic mutations in isocitrate dehydrogenase 1 (IDH1) gene occur frequently in primary brain tumors. Recently theses mutations were demonstrated in acute myeloid leukemia (AML). So far, assessment of these mutations relied on the DNA sequencing technique.Aim of the workThe aim of this study was to detect somatic mutations in IDH1 gene using mismatched primers suitable for endonuclease based detection, without the need for DNA sequencing, and to estimate its prognostic value, on patients with de novo AML.MethodsResidual DNA extracted from pretreatment bone marrow (BM) samples of 100 patients with de novo AML was used. The polymerase chain reaction-restriction fragment length polymorphism method (PCR-RFLP) was adapted to IDH1gene, codon 132 mutations screening.ResultsThe frequency of IDH1 mutations was 13%. In the non-acute promyelocytic leukemia group (non-APL), IDH1 mutations were significantly associated with FLT3-ITD negative patients (p = 0.03). Patients with IDH1 mutations did not achieve complete remission (CR). There was a trend for shorter overall survival (OS) in patients with IDH1 mutation compared to those with wild type (p = 0.08).ConclusionIDH1 mutations are recurring genetic alterations in AML and they may have unfavorable impact on clinical outcome in adult AML. The PCR-RFLP method allows for a fast, inexpensive, and sensitive method for the detection of IDH1 mutations in AML.     

Comparative examination of various PCR-based methods for DNMT3A and IDH1/2 mutations identification in acute myeloid leukemia

Background

Mutations in epigenetic modifiers were reported in patients with acute myeloid leukaemia (AML) including mutations in DNA methyltransferase 3A gene (DNMT3A) in 20%-30% patients and mutations in isocitrate dehydrogenase 1/2 gene (IDH1/2) in 5%-15% patients. Novel studies have shown that mutations in DNMT3A and IDH1/2 influence prognosis, indicating an increasing need to detect these mutations during routine laboratory analysis. DNA sequencing for the identification of these mutations is time-consuming and cost-intensive. This study aimed to establish rapid screening tests to identify mutations in DNMT3A and IDH1/2 that could be applied in routine laboratory procedures and that could influence initial patient management.

Methods

In this study we developed an endonuclease restriction method to identify the most common DNMT3A mutation (R882H) and an amplification-refractory mutation system (ARMS) to analyse IDH2 R140Q mutations. Furthermore, we compared these methods with HRM analysis and evaluated the latter for the detection of IDH1 mutations.

Results

Of 230 samples from patients with AML 30 (13%) samples had DNMT3A mutations, 16 (7%) samples had IDH2 R140Q mutations and 36 (16%) samples had IDH1 mutations. Sensitivity assays performed using serial dilutions of mutated DNA showed that ARMS analysis had a sensitivity of 4.5%, endonuclease restriction had a sensitivity of 0.05% and HRM analysis had a sensitivity of 5.9%–7.8% for detecting different mutations. HRM analysis was the best screening method to determine the heterogeneity of IDH1 mutations. Furthermore, for the identification of mutations in IDH2 and DNMT3A, endonuclease restriction and ARMS methods showed a perfect concordance (100%) with Sanger sequencing while HRM analysis showed a near-perfect concordance (approximately 98%).

Conclusion

Our study suggested that all the developed methods were rapid, specific and easy to use and interpret. HRM analysis is the most timesaving and cost-efficient method to rapidly screen all the 3 genes at diagnosis in samples obtained from patients with AML. Endonuclease restriction and ARMS assays can be used separately or in combination with HRM analysis to obtain more reliable results. We propose that early screening of mutations in patients with AML having normal karyotype could facilitate risk stratification and improve treatment options.     

IDH1、IDH2基因突变在肿瘤中的作用

异柠檬酸脱氢酶（IDH）是三羧酸循环中的一种关键酶,近年来在多种肿瘤中发现了频发的 IDH1、IDH2基因突变,这些突变特异性改变酶的催化活性,即直接催化α-酮戊二酸（α-KG）生成 R-2-羟戊二酸（R-2-HG）,竞争性抑制组蛋白和 DNA 去甲基酶等多种α-KG 依赖的双加氧酶,并可能由此促进肿瘤的发生发展,此外,IDH1、IDH2基因突变状态与肿瘤患者预后相关。IDH1、IDH2基因是一个潜在的肿瘤早期诊断、预后评估和靶向治疗的标志性基因。     

Analysis of IDH1 and IDH2 mutations in Japanese glioma patients

A recent study reported on mutations in the active site of the isocitrate dehydrogenase 1 ( IDH1 ) gene in several types of gliomas. All mutations detected resulted in an amino acid exchange at position 132. We analyzed the genomic region spanning wild-type R132 of IDH1 by direct sequencing in 125 glial tumors. A total of 39 IDH1 mutations were observed. Mutations of the IDH2 gene, homologous to IDH1 , were often detected in gliomas without IDH1 mutations. In the present study, R172 mutation of the IDH2 gene was detected in one anaplastic astrocytoma. IDH1 or IDH2 mutations were frequently in oligodendrogliomas (67%), anaplastic astrocytomas (62%), anaplastic oligoastrocytomas (75%), anaplastic oligodendrogliomas (50%), secondary glioblastomas (67%), gangliogliomas (38%), and anaplastic gangliogliomas (60%). Primary glioblastomas were characterized by a low frequency of mutations (5%) at amino acid position 132 of IDH1 . Mutations of the IDH1 or IDH2 genes were significantly associated with improved outcome in patients with anaplastic astrocytomas. Our data suggest that IDH1 or IDH2 mutation plays a role in early tumor progression of several types of glioma and might arise from a common glial precursor. The infrequency of IDH1 mutation in primary glioblastomas revealed that these subtypes are genetically distinct entities from other glial tumors. ( Cancer Sci  2009; 100: 1996–1998)     

Targeting IDH1 and IDH2 Mutations in Acute Myeloid Leukemia

Purpose of Review

Over the past decade, the pathogenic role of mutations in isocitrate dehydrogenases (IDH) 1 and 2, affecting approximately 20% of patients with AML, has been defined, allowing for the development of specific therapeutic strategies for IDH-mutant AML. In this review, the landscape and progress of targeted therapeutics aimed at IDH mutations in AML and related myeloid malignancies will be described.

Recent Findings

Since 2013, several mutant IDH-targeted inhibitors have been developed, and nearly a dozen clinical trials have opened specifically for IDH-mutant hematologic malignancies. Preliminary results for several of these investigations have shown evidence of safety, tolerability, and encouraging evidence of efficacy.

Summary

Targeting IDH mutations in AML is a biologically informed and rational strategy to promote clinical responses, primarily through differentiation and maturation of the malignant clone. The use of IDH targeted therapy is expected to soon become part of a genomically defined and individualized AML treatment strategy.

     

FLT3、NPM1、DNMT3A及IDH基因突变对非M3型急性髓系白血病预后影响的研究进展

非M3型急性髓系白血病(AML)是一组异质性恶性血液系统疾病,无论在形态学、免疫学、细胞遗传学、分子生物学及临床特点上都存在很大差异.细胞遗传学检测结果已经成为AML精确诊断、治疗选择和预后判断的主要依据之一,但由于在分子水平上存在高度的异质性,常规细胞遗传学技术检出率不高.有40%~50%的AML患者在初诊时用标准的染色体显带分析方法检测不到克隆性染色体畸变,被称为正常核型AML.非M3型AML较常见的分子遗传学改变为FLT3、NPM1、DNMT3A、IDH基因突变.文章主要就四种基因的特点、发病机制及对非M3型AML的预后影响作一综述.     

Acute myeloid leukemia

Acute myeloid leukemia (AML) has been treated with combination chemotherapy, hematopoietic stem cell transplantation (HSCT) and differentiation induction therapy. Intensive induction and consolidation therapy including high dose cytarabine (HDAC) is a widely used combination in chemotherapy in the USA and European countries. In Japan, the efficacy of HDAC needs to be evaluated under a good clinical trial. Stem cell source for HSCT has been expanded, and the number of peripheral blood stem cell transplantations is greater than that of bone marrow transplantation, especially for auto-transplantation. Despite some randomized clinical trials, we still do not know whether HSCT provides longer survival than chemotherapy for patients with AML when performed during their first remission. Differentiation therapy for acute promyelocytic leukemia (APL) using ATRA showed clear success in the treatment for AML. APL is stratified with its specific karyotype and morphology, and this stratification leads to the improvement of overall survival of patients with APL. Several clinical study groups in the world have studied prognostic factors and it has been shown that the chromosomal abnormality of AML cells is closely related to the response to the chemotherapy. The stratification of AML using these prognostic factors is incorporated in some clinical trials to determine whether this approach actually leads to better survival for patients with AML.     

Acute myeloid leukemia

Acute myeloid leukemia (AML) remains the most common form of acute leukemia among adults and accounts for the largest number of annual deaths due to leukemias in the United States. The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for AML provide recommendations on the diagnostic evaluation and workup for AML, risk assessment based on cytogenetic and molecular features, treatment options for induction and consolidation therapies for younger and older (age ≥ 65 years) adult patients, and key supportive care considerations.     

Acute myeloid leukemia

The heterogeneity of acute myeloid leukemia (AML) has been established by many new insights from molecular biological studies. In AML with favorable cytogenetic changes, KIT gene mutation has been known as a worse prognostic marker. Even in AML with normal cytogenetics, numerous molecular genetic alterations have been identified including internal tandem duplication of the FLT3 gene (FLT3-ITD), mutations in the NPM1 gene, mutations in the CEBPA gene, and partial tandem duplication of the MLL gene. Of these, FLT3-ITD has the most important prognostic implication. Insights into the molecular pathogenesis of AML have led to the development of more specific targeted agents. Currently, a number of agents have been explored in AML, including immunoconjugate of anti-CD33 antibody and cytotoxic agent (gemtuzumab ozogamicin: GO), tyrosine kinase inhibitors and farnesyl transferase inhibitor. These agents have shown promise in small studies. Large phase III studies will reveal whether these are effective in inducing complete remission and prolonging survival. Combining targeted agents with each other or with chemotherapy may improve the response rates. GO is the most promising drug, which has been evaluated in randomized trials by several major cooperative groups to determine whether the addition of GO improves the complete remission rate and overall survival. In the near future AML may be classified and treated by their molecular biological alterations.     

Acute myeloid leukemia

The annual incident rate of pediatric acute myeloid leukemia (AML) is now 10 per million in Japan, against 5 to 9 per million in the USA and Europe. Overall long-term survival has now been achieved for more than 50% of pediatric patients with AML in the USA and in Europe. The prognostic factors of pediatric AML were analyzed,and patients with AML were classified according to prognostic factors. The t(15;17), inv(16) and t(8;21) have emerged as predictors of good prognosis in children with AML. Monosomy 7, monosomy 5 and del (5 q) abnormalities showed a poor prognosis. In addition to chromosomal deletions, FLT 3/ITD identifies pediatric patients with a particularly poor prognosis. Clinical trials of AML feature intensive chemotherapy with or without subsequent stem cell transplantation. Risk group stratification is becoming increasingly important in planning AML therapy. APL can be distinguished from other subtypes of AML by virtue of its excellent response and overall outcome as a result of differentiation therapy with ATRA. Children with Down syndrome and AML have been shown to have a superior prognosis to AML therapy compared to other children with AML. The results of the Japan Cooperative Study Group protocol ANLL 91 was one of the best previously reported in the literature. With the consideration of quality of life (QOL), risk-adapted therapy was introduced in the AML 99 trial conducted by the Japanese Childhood AML Cooperative Study Group. A high survival rate of 79% at 3 years was achieved for childhood de novo AML in the AML 99 trial. To evaluate the efficacy and safety of the treatment strategy according to risk stratification based on leukemia cell biology and response to the initial induction therapy in children with AML, the Japanese Pediatric Leukemia/Lymphoma Study Group (JPLSG) has organized multi-center phase II trials in children with newly diagnosed AML.     

IDH1/2 but not DNMT3A mutations are suitable targets for minimal residual disease monitoring in acute myeloid leukemia patients: a study by the Acute Leukemia French Association

Acute myeloid leukemia (AML) is a heterogeneous disease. Even within the same NPM1-mutated genetic subgroup, some patients harbor additional mutations in FLT3, IDH1/2, DNMT3A or TET2. Recent studies have shown the prognostic significance of minimal residual disease (MRD) in AML but it remains to be determined which molecular markers are the most suitable for MRD monitoring. Recent advances in next-generation sequencing (NGS) have provided the opportunity to use multiple molecular markers. In this study, we used NGS technology to assess MRD in 31 AML patients enrolled in the ALFA-0701 trial and harboring NPM1 mutations associated to IDH1/2 or DNMT3A mutations. NPM1 mutation-based MRD monitoring was performed by RTqPCR. IDH1/2 and DNMT3A mutations were quantified by NGS using an Ion Torrent Proton instrument with high coverage (2 million reads per sample). The monitoringof IDH1/2 mutations showed that these mutations were reliable MRD markers that allowed the prediction of relapse in the majority of patients. Moreover, IDH1/2 mutation status predicted relapse or disease evolution in 100% of cases if we included the patient who developed myelodysplastic syndrome. In contrast, DNMT3A mutations were not correlated to the disease status, as we found that a preleukemic clone with DNMT3A mutation persisted in 40% of the patients who were in complete remission, reflecting the persistence of clonal hematopoiesis.     

老年人急性髓系白血病治疗进展

 老年急性髓性白血病（AML）患者的预后在最近30年间没有明显改善,老年患者的特点限制了其耐受强烈化疗的能力并且导致更高的早期死亡率。老年AML患者很大一部分有既往血液学疾病史,其白血病细胞有预后不良的遗传学异常,表达多药耐药基因（MDR1）,这些特点导致对化疗耐药。近30年间研究、应用了许多方法。现对老年AML患者治疗研究进展作一综述。     

Acute myeloid leukemia: epidemiology and etiology

Acute myeloid leukemias (AMLs) are infrequent, yet highly malignant neoplasms responsible for a large number of cancer-related deaths. The incidence has been near stable over the last years. It continuously shows 2 peaks in occurrence in early childhood and later adulthood. With an incidence of 3.7 per 100,000 persons and an age-dependent mortality of 2.7 to nearly 18 per 100,000 persons, there is a rising awareness in the Western world of AML's special attributes resulting from an ever-aging population. To objectively describe epidemiologic data on this patient population, recent publications were evaluated to make transparent the current trends and facts. A review of the literature is presented, reflecting highlights of current research with respect to AML etiology. To estimate outcome and discuss informed treatment decisions with AML patients of different age groups and different biologic risk categories, it is mandatory to consider that the outcome results reported in clinical trials were until now heavily biased toward younger patients, whereas the overall dismal prognosis documented in population-based studies most likely reflects the exclusion of older patients from aggressive treatment. The etiology for most cases of AML is unclear, but a growing knowledge concerning leukemogenenic agents within chemotherapy regimens for other malignancies is already available. This includes specific associations of the most frequent balanced translocations in AML, including the "good-risk" abnormalities comprised by the core binding factor leukemias (i.e., AML with the translocation (8;21) and inversion of chromosome 16, and acute promyelocytic leukemia with the translocation (15;17)). In contrast to these genetic alterations, epigenetic lesions, e.g., promoter silencing by hypermethylation of the p15/INK4b and other genes, are increasingly recognized as important in the pathogenesis of AML.     

Phospholipid metabolic adaptation promotes survival of IDH2 mutant acute myeloid leukemia cells

Genetic mutations in the isocitrate dehydrogenase (IDH) gene that result in a pathological enzymatic activity to produce oncometabolite have been detected in acute myeloid leukemia (AML) patients. While specific inhibitors that target mutant IDH enzymes and normalize intracellular oncometabolite level have been developed, refractoriness and resistance has been reported. Since acquisition of pathological enzymatic activity is accompanied by the abrogation of the crucial WT IDH enzymatic activity in IDH mutant cells, aberrant metabolism in IDH mutant cells can potentially persist even after the normalization of intracellular oncometabolite level. Comparisons of isogenic AML cell lines with and without IDH2 gene mutations revealed two mutually exclusive signalings for growth advantage of IDH2 mutant cells, STAT phosphorylation associated with intracellular oncometabolite level and phospholipid metabolic adaptation. The latter came to light after the oncometabolite normalization and increased the resistance of IDH2 mutant cells to arachidonic acid-mediated apoptosis. The release of this metabolic adaptation by FDA-approved anti-inflammatory drugs targeting the metabolism of arachidonic acid could sensitize IDH2 mutant cells to apoptosis, resulting in their eradication in vitro and in vivo. Our findings will contribute to the development of alternative therapeutic options for IDH2 mutant AML patients who do not tolerate currently available therapies.     

IDH1 and IDH2 mutations,immunohistochemistry and associations in a series of brain tumors

A total of 343 brain tumors were studied for IDH1 and IDH2 mutations by direct sequencing and for protein expression by immunohistochemistry with mIDH1^R132H antibody. Of these, 287 were gliomas (17 pilocytic astrocytomas, 13 grade II and 5 grade III astrocytomas, 167 primary (pGBMs) and 19 secondary (sGBMs) glioblastomas, 36 grade II and 26 grade III oligodendrogliomas and 4 grade II–III oligoastrocytomas). In gliomas, IDH1 mutations at codon R132 were identified in 22.3%, of which 93.7% were c.395G>A (p.R132H). Mutations were more frequent in oligodendrogliomas (53.2%) than in astrocytic tumors (22.8%) and in sGBMs (84.2%) upon pGBMs (1.8%). There was a statistically significant correlation between mIDH1^R132H antibody immunostaining and the relevant mutation c.395G>A (p.R132H) (P = 0.0001). No mutations were identified in non-glial tumors which were also negative to immunohistochemistry, with the exception of one PNET. A c.515G>T (p.R172M) mutation of the IDH2 gene was only identified in a grade II oligodendroglioma patient which was wild-type for IDH1. A direct correlation with MGMT promoter hypermethylation status and an inverse correlation with EGFR amplification was found, whereas the relationships with 1p/19q co-deletion and TP53 mutations only showed a trend toward correlation. In all gliomas, a positive correlation was found between IDH1 mutations and a young age (P = 0.0001). In contrast, a correlation with overall survival could only be obtained in low-grade gliomas. Immunohistochemistry appeared to be useful in differential diagnoses, especially toward non-tumor pathologic nervous tissue, and in recognizing infiltrating glioma cells. The mIDH1^R132H antibody positivity was complementary with Cyclin D1 expression.