Correlation Between Isocitrate Dehydrogenase Gene Aberrations and Prognosis of Patients with Acute Myeloid Leukemia: A Systematic Review and Meta-Analysis

Ivosidenib in Chinese patients with relapsed or refractory isocitrate dehydrogenase 1 mutated acute myeloid leukemia: a registry study

Ivosidenib, an isocitrate dehydrogenase 1 (IDH1) inhibitor, has demonstrated clinical benefits in a pivotal study (AG120-C-001) in patients with IDH1-mutated (mIDH1) acute myeloid leukemia (AML). A registry study (CS3010-101: NCT04176393) was conducted to assess the pharmacokinetic (PK) characteristics, safety, and efficacy of ivosidenib in Chinese patients with relapsed or refractory (R/R) mIDH1 AML. Patients received ivosidenib 500 mg once daily for 28-day cycles until disease progression. Ten subjects underwent intensive PK/progressive disease (PD) assessments. All subjects had the clinical response assessed at screening, every 28 days through month 12, and then every 56 days. Between November 12, 2019, and April 2, 2021, 30 patients were enrolled; 26 (86.7%) had de novo AML and 18 (60.0%) were transfusion-dependent at baseline. Following single and repeated doses of ivosidenib, median time to maximum plasma concentration (T max) was 4.0 and 2.0 hours, respectively. The inter-individual variability of pharmacokinetic exposure was moderate to high (coefficient of variation [CV], 25%-53%). No obvious accumulation was observed after repeated doses at cycle 2 day 1. Regarding the clinical response, the CR + CRh rate was 36.7% (95% confidence interval [CI]: 19.9%-56.1%), the median duration of CR + CRh was 19.7 months (95% CI: 2.9 months-not reached [NR]), and median duration of response (DoR) was 14.3 months (95% CI: 6.4 months-NR). Consistent clinical benefits and safety of ivosidenib were consistently observed at the final data cutoff with median follow-up time 26.0 months, as compared with primary data cutoff, and the data from Chinese R/R mIDH1 AML patients were also consistent with results from pivotal study.

Emerging DNA Methylome Targets in FLT3-ITD-Positive Acute Myeloid Leukemia: Combination Therapy with Clinically Approved FLT3 Inhibitors

OPINION STATEMENT

The internal tandem duplication (ITD) mutation of the FMS-like receptor tyrosine kinase 3 (FLT3-ITD) is the most common mutation observed in approximately 30% of acute myeloid leukemia (AML) patients. It represents poor prognosis due to continuous activation of downstream growth-promoting signaling pathways such as STAT5 and PI3K/AKT. Hence, FLT3 is considered an attractive druggable target; selective small FLT3 inhibitors (FLT3Is), such as midostaurin and quizartinib, have been clinically approved. However, patients possess generally poor remission rates and acquired resistance when FLT3I used alone. Various factors in patients could cause these adverse effects including altered epigenetic regulation, causing mainly abnormal gene expression patterns. Epigenetic modifications are required for hematopoietic stem cell (HSC) self-renewal and differentiation; however, critical driver mutations have been identified in genes controlling DNA methylation (such as DNMT3A, TET2, IDH1/2). These regulators cause leukemia pathogenesis and affect disease diagnosis and prognosis when they co-occur with FLT3-ITD mutation. Therefore, understanding the role of different epigenetic alterations in FLT3-ITD AML pathogenesis and how they modulate FLT3I's activity is important to rationalize combinational treatment approaches including FLT3Is and modulators of methylation regulators or pathways. Data from ongoing pre-clinical and clinical studies will further precisely define the potential use of epigenetic therapy together with FLT3Is especially after characterized patients' mutational status in terms of FLT3 and DNA methlome regulators.

Altered Oxidative Phosphorylation Confers Vulnerability on IDH1-Mutant Leukemia Cells: Is This Therapeutically Tractable?

SUMMARY

Isocitrate dehydrogenase (IDH)-mutant acute myeloid leukemia (AML) is treatable with inhibitors of mutant IDH and also responds well to combination therapies including venetoclax, but most patients with IDH-mutant AML either never achieve complete remission or relapse because mutant hematopoietic stem cells persist despite treatment. An interesting new study in Blood Cancer Discovery characterizes a specific vulnerability in the mitochondrial oxidative phosphorylation system in preleukemic hematopoietic stem cells from patients with IDH1 mutations that is not present in those with IDH2 mutations; will this susceptibility prove amenable to therapy? See related article by Landberg et al., p. 114 (10).

IDH2 mutations in acute myeloid leukemia

Advances in the treatment of acute myeloid leukemia (AML) over the last 40 years have been limited. With an improved understanding of the pathophysiology of the disease, the advent of new treatment options has enriched the armamentarium of the physician to combat the disease. Mutations of the isocitrate dehydrogenase (IDHs) genes are common in AML and occur in 20-30% of cases. These mutations lead to DNA hypermethylation, aberrant gene expression, cell proliferation, and abnormal differentiation. Targeting mutant IDH, either as monotherapy or in combination with hypomethylating agents (HMAs) or BCL-2 inhibitors, has opened new avenues of therapy for these patients.This review will outline the function of IDHs and focus on the biological effects of IDH2 mutations in AML, their prognosis and treatment options.

Ivosidenib in acute myeloid leukemia

INTRODUCTION

Traditional treatment strategies for acute myeloid leukemia (AML) have primarily relied on standard chemotherapy regimens for four decades. Indeed, the landscape of AML therapy has evolved substantially in recent years, mainly due to the introduction of hypomethylating agents and small molecules.Bcl2 inhibitor venetoclax, Fms-like tyrosine kinase 3 (FLT3) inhibitors such as midostaurin and gilteritinib, and isocitrate dehydrogenases 1 and 2 (IDH1 and IDH2) inhibitors ivosidenib and enasidenib, as well as hedgehog (HH) pathway inhibitor glasdegib represented a significant step forward in AML therapeutic armamentarium. Smoothened (SMO) inhibitor in combination with low-dose cytarabine marks a recent milestone.

AREAS COVERED

Ivosidenib, the first-in-class, selective, allosteric IDH1R132 inhibitor, showed the capability to induce in vitro differentiation of primary mIDH1 AML blasts. Clinical data highlighted its exceptional safety profile, as a standalone therapy and in combination strategy. Additionally, comprehensive studies consistently demonstrated its effectiveness, both in monotherapy and in association with chemotherapy.

EXPERT OPINION

The identified ivosidenib's strengths, including its remarkable safety record and ability to yield positive therapeutic outcomes, position it as an ideal partner for both classic chemotherapy and biological treatments, i.e. hypometilant agents and/or venetoclax. Further studies are warranted to explore strategies for overcoming the occurrence of ivosidenib resistance.

The curious case of IDH mutant acute myeloid leukaemia: biochemistry and therapeutic approaches

Of the many genetic alterations that occur in cancer, relatively few have proven to be suitable for the development of targeted therapies. Mutations in isocitrate dehydrogenase (IDH) 1 and -2 increase the capacity of cancer cells to produce a normally scarce metabolite, D-2-hydroxyglutarate (2-HG), by several orders of magnitude. The discovery of the unusual biochemistry of IDH mutations spurred a flurry of activity that revealed 2-HG as an 'oncometabolite' with pleiotropic effects in malignant cells and consequences for anti-tumour immunity. Over the next decade, we learned that 2-HG dysregulates a wide array of molecular pathways, among them a large family of dioxygenases that utilise the closely related metabolite α-ketoglutarate (α-KG) as an essential co-substrate. 2-HG not only contributes to malignant transformation, but some cancer cells become addicted to it and sensitive to inhibitors that block its synthesis. Moreover, high 2-HG levels and loss of wild-type IDH1 or IDH2 activity gives rise to synthetic lethal vulnerabilities. Herein, we review the biology of IDH mutations with a particular focus on acute myeloid leukaemia (AML), an aggressive disease where selective targeting of IDH-mutant cells is showing significant promise.

The impact of IDH and NAT2 gene polymorphisms in acute myeloid leukemia risk and overall survival in an Arab population: A case-control study

Acute myeloid leukemia (AML) is a malignancy of the myeloid cells due to the clonal and malignant proliferation of blast cells. The etiology of AML is complex and involves environmental and genetic factors. Such genetic aberrations include FLT3, DNMT3, IDH1, IDH2, NAT2, and WT. In this study, we analyzed the relationship between five, not previously studied in any Arab population, single nucleotide polymorphisms (SNPs) and the risk and overall survival of AML in Jordanian patients. The SNPs are NAT2 (rs1799930 and rs1799931), IDH1 (rs121913500), and IDH2 (rs121913502 and rs1057519736). A total number of 30 AML patients and 225 healthy controls were included in this study. Females comprised 50% (n = 15) and 65.3% (n = 147) of patients and controls, respectively. For AML patients (case group) Genomic DNA was extracted from formalin-fixed paraffin-embedded tissues and from peripheral blood samples for the control subjects group. Genotyping of the genetic polymorphisms was conducted using a sequencing protocol. Our study indicates that NAT2 rs1799930 SNP had a statistically significant difference in genotype frequency between cases and controls (p = 0.023) while IDH mutations did not correlate with the risk and survival of AML in the Jordanian population. These results were also similar in the TCGA-LAML cohorts with the notable exception of the rare NAT2 mutation. A larger cohort study is needed to further investigate our results.

Efficacy and safety of FDA-approved IDH inhibitors in the treatment of IDH mutated acute myeloid leukemia: a systematic review and meta-analysis

OBJECTIVE

To systematically evaluate the efficacy and safety of FDA-approved isocitrate dehydrogenase (IDH) inhibitors in the treatment of IDH-mutated acute myeloid leukemia (AML).

METHODS

We used R software to conduct a meta-analysis of prospective clinical trials of IDH inhibitors in the treatment of IDH-mutated AML published in PubMed, Embase, Clinical Trials, Cochrane Library and Web of Science from inception to November 15th, 2022.

RESULTS

A total of 1109 IDH-mutated AML patients from 10 articles (11 cohorts) were included in our meta-analysis. The CR rate, ORR rate, 2-year survival (OS) rate and 2-year event-free survival (EFS) rate of newly diagnosed IDH-mutated AML (715 patients) were 47%, 65%, 45% and 29%, respectively. The CR rate, ORR rate, 2-year OS rate, median OS and median EFS of relapsed or refractory (R/R) IDH-mutated AML (394 patients) were 21%, 40%, 15%, 8.21 months and 4.73 months, respectively. Gastrointestinal adverse events were the most frequently occurring all-grade adverse events and hematologic adverse events were the most frequently occurring ≥ grade 3 adverse events.

CONCLUSION

IDH inhibitor is a promising treatment for R/R AML patients with IDH mutations. For patients with newly diagnosed IDH-mutated AML, IDH inhibitors may not be optimal therapeutic agents due to low CR rates. The safety of IDH inhibitors is controllable, but physicians should always pay attention to and manage the differentiation syndrome adverse events caused by IDH inhibitors. The above conclusions need more large samples and high-quality RCTs in the future to verify.

A case report of complete remission of acute myeloid leukemia combined with DNMT3A, FLT3-TKD, and IDH2 gene mutations and active pulmonary tuberculosis treated with homeharringtonine + venetoclax + azacytidine

In March 2022, a 58-year-old man was admitted to the local hospital for nausea and vomiting. His blood routine indicated that he had leukocytosis and anemia. The patient was diagnosed with acute myeloid leukemia (AML)-M5b accompanied by DNMT3A, FLT3-TKD, and IDH2 mutations, chest CT revealed pulmonary tuberculosis (TB). Acid-fast bacillus (AFB) was detected in sputum. The patient then received anti-TB treatment with isoniazid + rifampicin + pyrazinamide + ethambutol. On April 8, he was transferred to our hospital's Hematology Department after three consecutive negative sputum smears. He was administered the VA (Venetoclax + Azacytidine) regimen of anti-leukemia treatment and also received levofloxacin + isohydrazide + pyrazinamide + ethambutol anti-TB treatment. After one course of VA therapy, there was no remission in the bone marrow. Therefore, the patient received the HVA (Homeharringtonine + Venetoclax + Azacytidine) regimen of anti-leukemia treatment. On May 25, the bone marrow smear revealed that the original mononuclear cells were 1%. Moreover, bone marrow flow cytometry revealed the absence of any abnormal cells. mNGS showed DNMT3A (mutation rate 44.7%), but no mutations were detected in FLT3-TKD and IDH2. The patient then received the HVA regimen three consecutive times, resulting in complete remission. Repeated chest CT examinations revealed progressive regression of pulmonary TB foci, no AFB was detected in the sputum. This AML patient with DNMT3A, FLT3-TKD, and IDH2 mutations and active TB is difficult to treat. It is very necessary for him to administer prompt anti-leukemia treatment under the premise of active anti-TB treatment. The HVA regimen is effective for this patient.

Prognostic value of IDH2R140 and IDH2R172 mutations in patients with acute myeloid leukemia: a systematic review and meta-analysis

BACKGROUND

Whether isocitrate dehydrogenase 2 (IDH2) R140 and R172 gene mutations affect the prognosis of patients with acute myeloid leukemia (AML) is controversial. Here, we performed a meta-analysis to assess their prognostic value.

METHODS

Eligible studies were systematically searched from PubMed, Embase, the Cochrane Library and Chinese databases up to June 1, 2022. We extracted the hazard ratios (HRs) and their 95% confidence intervals (CIs) of overall survival (OS) and progression-free survival (PFS) to carry out a meta-analysis by a fixed effect model or random effect model according to the heterogeneity between studies.

RESULTS

A total of 12725 AML patients from 11 studies were included in this meta-analysis, of which 1111 (8.7%) and 305 (2.4%) had IDH2R140 and IDH2R172 mutations, respectively. The results revealed that both IDH2R140 and IDH2R172 mutations had no significant effect on OS (IDH2R140: HR = 0.92, 95% CI: 0.77-1.10, P = 0.365; IDH2R172: HR = 0.91, 95% CI: 0.65-1.28, P = 0.590) or PFS (IDH2R140: HR = 1.02, 95% CI: 0.75-1.40, P = 0.881; IDH2R172: HR = 1.31, 95% CI: 0.78-2.22, P = 0.306) in AML patients. Subgroup analysis of AML patients with IDH2R140 mutation revealed that studies from the USA (HR = 0.60, 95% CI: 0.41-0.89, P = 0.010) and ≤ 50 years old (HR = 0.63, 95% CI: 0.50-0.80, P = 0.000) had longer OS. However, studies from Sweden (HR = 1.94, 95% CI: 1.07-3.53, P = 0.030) had shorter OS. Meanwhile, subgroup analysis of AML patients with IDH2R172 mutation showed that studies from Germany/Austria (HR = 0.76, 95% CI: 0.61-0.94, P = 0.012) and from Sweden (HR = 0.22, 95% CI: 0.07-0.74, P = 0.014) had longer OS, whereas studies from the UK (HR = 1.49, 95% CI: 1.13-1.96, P = 0.005) and studies with nonmultivariate analysis of data type (HR = 1.35, 95% CI: 1.06-1.73, P = 0.014) had shorter OS. In addition, our study also found that patients with IDH2R140 mutation had significantly longer OS (HR = 0.61, 95% CI: 0.39-0.96, P = 0.032) and PFS (HR = 0.31, 95% CI: 0.18-0.52, P = 0.021) than patients with IDH2R172 mutation, despite some degree of heterogeneity.

CONCLUSIONS

This meta-analysis demonstrates that IDH2R140 mutation improves OS in younger AML patients and that the prognostic value of IDH2R172 mutation is significantly heterogeneous. Differences in region and data type have a significant impact on the prognosis of AML patients with IDH2R140 and/or IDH2R172 mutations. Additionally, AML patients with IDH2R140 mutation have a better prognosis than those with IDH2R172 mutations, albeit with some degree of heterogeneity.

A Study to Explore the Role of IDH1 (R132) Mutation on Imatinib Toxicity and Effect of ABCG2/OCT1 Expression on N-Desmethyl Imatinib Plasma Level in Egyptian Chronic Myeloid Leukemia Patients

Imatinib mesylate (IM) is the gold standard for treatment of Chronic Myeloid Leukemia (CML). This study aimed to gain more knowledge of the altered PK, pharmacogenetic factors, and gene expression leading to variable IM levels. Fifty patients with chronic phase-CML were enrolled in this study and divided as 25 responders and 25 non-responders (patients are directly recruited after response assessment). HPLC/MS/MS was used to determine trough and peak concentration of imatinib and N-desmethyl imatinib in the blood. PCR-RFLP technique was used to detect IDH1 gene mutation (R132). The median value of IM trough level was significantly higher, the P/T ratio was significantly lower and the α-1-acid glycoprotein (AGP) was significantly higher among responders compared to non-responders (P=0.007, 0.009 and 0.048, respectively). Higher N-desmethyl imatinib peak plasma concentration was observed with low mRNA expression of ABCG2 and OCT1 (P=0.01 and 0.037, respectively). IDH1 R132 gene mutation was associated with a significant increase in toxicities (P=0.028). In conclusion, IM trough level, P/T ratio and AGP was significantly higher in responders. In addition, ABCG2 and OCT1 gene expression may affect the interindividual PK variation. Although a prospective study with a larger patient population is necessary to validate these findings. IDH1 mutation is a predictor of increased toxicity with IM treatment.

IDH2 stabilizes HIF-1α-induced metabolic reprogramming and promotes chemoresistance in urothelial cancer

Drug resistance contributes to poor therapeutic response in urothelial carcinoma (UC). Metabolomic analysis suggested metabolic reprogramming in gemcitabine-resistant urothelial carcinoma cells, whereby increased aerobic glycolysis and metabolic stimulation of the pentose phosphate pathway (PPP) promoted pyrimidine biosynthesis to increase the production of the gemcitabine competitor deoxycytidine triphosphate (dCTP) that diminishes its therapeutic effect. Furthermore, we observed that gain-of-function of isocitrate dehydrogenase 2 (IDH2) induced reductive glutamine metabolism to stabilize Hif-1α expression and consequently stimulate aerobic glycolysis and PPP bypass in gemcitabine-resistant UC cells. Interestingly, IDH2-mediated metabolic reprogramming also caused cross resistance to CDDP, by elevating the antioxidant defense via increased NADPH and glutathione production. Downregulation or pharmacological suppression of IDH2 restored chemosensitivity. Since the expression of key metabolic enzymes, such as TIGAR, TKT, and CTPS1, were affected by IDH2-mediated metabolic reprogramming and related to poor prognosis in patients, IDH2 might become a new therapeutic target for restoring chemosensitivity in chemo-resistant urothelial carcinoma.

Prognostic significance of KMT2A-PTD in patients with acute myeloid leukaemia: a systematic review and meta-analysis

OBJECTIVES

Whether KMT2A-PTD has a prognostic impact on patients with acute myeloid leukaemia (AML) is controversial. Therefore, we conducted a meta-analysis to assess the prognostic value of KMT2A-PTD in patients with AML.

METHODS

Eligibility criteria: we included studies concerning the prognostic value of KMT2A-PTD in patients with AML.

INFORMATION SOURCES

Eligible studies were identified from PubMed, Embase, Medline, Web of Science, Cochrane Library and Chinese Biomedical Database. The systematic search date was 19 December 2020.Risk of bias: Sensitivity analysis was used to evaluate the stability and reliability of the combined results. Begg's and Egger's tests were used to assess the publication biases of studies.

SYNTHESIS OF RESULTS

We calculated the pooled HRs and their 95% CIs for overall survival (OS) and event-free survival (EFS) by Stata V.12 software.

RESULTS

Included studies: 18 studies covering 6499 patients were included.

SYNTHESIS OF RESULTS

KMT2A-PTD conferred shorter OS in total population (HR=1.30, 95% CI 1.09 to 1.51). In the subgroup analysis, KMT2A-PTD also resulted in shorter OS in karyotypically normal AML patients (HR=2.72, 95% CI 1.83 to 3.61) and old AML patients (HR=1.93, 95% CI 1.44 to 2.42). KMT2A-PTD indicated no prognostic impact on EFS in total population (HR=1.26, 95% CI 0.86 to 1.66). However, in the sensitivity analysis, KMT2A-PTD resulted in poor EFS (HR=1.34, 95% CI 1.04 to 1.64) when deleting the study with a relatively obvious effect on the combined HR. In the subgroup analysis, KMT2A-PTD was associated with poor EFS in old AML patients (HR=1.64, 95% CI 1.25 to 2.03).

CONCLUSION

The findings indicated that KMT2A-PTD had an adverse impact on the prognosis of patients with AML in the total population, and the conclusion can also be applied to some subgroups including karyotypically normal AML and old AML patients. KMT2A-PTD may be a promising genetic biomarker in patients with AML in the future.

TRIAL REGISTRATION NUMBER

CRD42021227185.

Oral Antineoplastics in Acute Myeloid Leukemia: A Comprehensive Review

AML is a biologically and clinically heterogeneous disease that is associated with poor overall long-term survival. The expanding knowledge of genomic landscape in AML as well as advancements in molecular and chemical biology over the pathway in AML. After 40 years of stagnancy, the recent approval of numerous novel oral anti-leukemic agents for the treatment of AML has changed both the armamentarium of medications and treatment paradigms. These agents have unique clinical considerations in terms of administration, adverse effects, and monitoring parameters which may differ from clinician's historical expectations. Understanding the data, indication and clinical considerations for such novel oral anti-leukemic agents is paramount for clinicians caring patients with AML.

Impact of mutations in epigenetic modifiers in acute myeloid leukemia: A systematic review and meta-analysis

This is a systematic review and meta-analysis evaluating the prognostic significance of epigenetic mutations on the overall survival (OS) in Acute Myeloid Leukemia (AML). We searched for studies evaluating epigenetic mutations in AML (up to November 2018) in PubMed, Trip database and Cochrane library. Hazard ratio (HR) of outcomes were extracted, and random-effects model was used to pool the results. A total of 10,002 citations were retrieved from the search strategy; 42 articles were identified for the meta-analysis (ASXL1 = 7, TET2 = 8, DNMT3A = 12, IDH =15), with fair to good-quality studies. The pooled HR was 1.88 (95% CI: 1.49-2.36) for ASXL1 mutation, 1.39 (95% CI: 1.18-1.63) for TET2 mutation, 1.35 (95% CI 1.16-1.56) for DNMT3a and 1.54 (95% CI: 1.15-2.06) for IDH mutation. However, there was a substantial heterogeneity in the DNMT3a and IDH studies. In conclusion epigenetic mutations in ASXL1, TET2, DNMT3a and IDH adversely impact OS in patients with AML albeit with considerable heterogeneity and possibly publication bias. Further studies are required to address these limitations.

Polyclonal evolution of Fanconi anemia to MDS and AML revealed at single cell resolution

Background

Fanconi anemia (FA) is a rare disease of bone marrow failure. FA patients are prone to develop myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). However, the molecular clonal evolution of the progression from FA to MDS/AML remains elusive.

Methods

Herein, we performed a comprehensive genomic analysis using an FA patient (P1001) sample that transformed to MDS and subsequently AML, together with other three FA patient samples at the MDS stage.

Results

Our finding showed the existence of polyclonal pattern in these cases at MDS stage. The clonal evolution analysis of FA case (P1001) showed the mutations of UBASH3A, SF3B1, RUNX1 and ASXL1 gradually appeared at the later stage of MDS, while the IDH2 alteration become the dominant clone at the leukemia stage. Moreover, single-cell sequencing analyses further demonstrated a polyclonal pattern was present at either MDS or AML stages, whereas IDH2 mutated cell clones appeared only at the leukemia stage.

Conclusions

We thus propose a clonal evolution model from FA to MDS and AML for this patient. The results of our study on the clonal evolution and mutated genes of the progression of FA to AML are conducive to understanding the progression of the disease that still perplexes us.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40164-022-00319-5.

Prognostic Analysis of the IDH1 G105G (rs11554137) SNP in IDH-Wildtype Glioblastoma

The G105G SNP (rs11554137) in the IDH1 gene is observed in about 10–15% of patients with a diffuse glioma. Data regarding its impact on gliomas are poor and partially conflicting, possibly due to the evolving classification of CNS tumors. The aim of this study was to investigate the G105G SNP prognostic significance in a homogenous cohort of IDH-wildtype glioblastomas, in agreement with the 2021 WHO classification. The study analyzed 211 patients by collecting several clinico-pathological and molecular characteristics, including the age, lesion localization, number of involved lobes, type of surgical treatment, disease outcome and MGMT promoter methylation status. PFS and DSS curves were plotted according to the Kaplan–Meier method and statistical analyses were performed using parametric and non-parametric tests. A total of 32 patients out of 211 (15.2%) were found to be G105G SNP carriers. No significant impact of the IDH1 G105G SNP on patients’ outcomes was observed in terms of PFS and DSS, while MGMT promoter methylation and gross total resection resulted as key prognostic factors in our cohort as expected. No prognostic impact of the IDH1 G105G SNP was detected in this strict cohort of IDH-wildtype glioblastomas. Analysis of larger cohorts is warranted to address the sample size limitations.

2-Hydroxyglutarate in Acute Myeloid Leukemia: A Journey from Pathogenesis to Therapies

The oncometabolite 2-hydroxyglutarate (2-HG) plays a key role in differentiation blockade and metabolic reprogramming of cancer cells. Approximatively 20–30% of acute myeloid leukemia (AML) cases carry mutations in the isocitrate dehydrogenase (IDH) enzymes, leading to a reduction in the Krebs cycle intermediate α-ketoglutarate (α-KG) to 2-HG. Relapse and chemoresistance of AML blasts following initial good response to standard therapy account for the very poor outcome of this pathology, which represents a great challenge for hematologists. The decrease of 2-HG levels through pharmacological inhibition of mutated IDH enzymes induces the differentiation of AML blasts and sensitizes leukemic cells to several anticancer drugs. In this review, we provide an overview of the main genetic mutations in AML, with a focus on IDH mutants and the role of 2-HG in AML pathogenesis. Moreover, we discuss the impact of high levels of 2-HG on the response of AML cells to antileukemic therapies and recent evidence for highly efficient combinations of mutant IDH inhibitors with other drugs for the management of relapsed/refractory (R/R) AML.

Synonymous Variants: Necessary Nuance in our Understanding of Cancer Drivers and Treatment Outcomes

Once called "silent mutations" and assumed to have no effect on protein structure and function, synonymous variants are now recognized to be drivers for some cancers. There have been significant advances in our understanding of the numerous mechanisms by which synonymous single nucleotide variants (sSNVs) can affect protein structure and function by affecting pre-mRNA splicing, mRNA expression, stability, folding, miRNA binding, translation kinetics, and co-translational folding. This review highlights the need for considering sSNVs in cancer biology to gain a better understanding of the genetic determinants of human cancers and to improve their diagnosis and treatment. We surveyed the literature for reports of sSNVs in cancer and found numerous studies on the consequences of sSNVs on gene function with supporting in vitro evidence. We also found reports of sSNVs that have statistically significant associations with specific cancer types but for which in vitro studies are lacking to support the reported associations. Additionally, we found reports of germline and somatic sSNVs that were observed in numerous clinical studies and for which in silico analysis predicts possible effects on gene function. We provide a review of these investigations and discuss necessary future studies to elucidate the mechanisms by which sSNVs disrupt protein function and are play a role in tumorigeneses, cancer progression, and treatment efficacy. As splicing dysregulation is one of the most well recognized mechanisms by which sSNVs impact protein function, we also include our own in silico analysis for predicting which sSNVs may disrupt pre-mRNA splicing.

Isocitrate dehydrogenase mutations are associated with altered IL-1β responses in acute myeloid leukemia

Mutations in isocitrate dehydrogenase 2 (IDH2) have been noted to impact cellular differentiation in addition to DNA and histone methylation. However, little is known about the impact of IDH2 mutations on intracellular signaling. Using an isogenic cell line model, we investigated both differentiation and signaling responses in IDH2 mutant cells and show augmented responses to inflammatory immune ligands. Using phospho-specific flow and mass cytometry, we demonstrate IDH2 mutant cells were significantly more sensitive to IL-1β at multiple downstream readouts. Further, bulk RNA sequencing confirmed increases in cytokine-related signaling pathways and NF-κB target genes. Single-cell RNA sequencing of unstimulated and stimulated cells confirmed altered IL-1β transcriptional responses in the IDH2 mutant cells. Targeted inhibition of the IKK complex reduced IL-1β responses and induced cell death in primary IDH-mutated leukemia samples. Together, these results confirm altered IL-1β signaling in IDH2 mutant cells and identify this pathway as a potential therapeutic target.

Reductive TCA cycle catalyzed by wild-type IDH2 promotes acute myeloid leukemia and is a metabolic vulnerability for potential targeted therapy

Background

Isocitrate dehydrogenase-2 (IDH2) is a mitochondrial enzyme that catalyzes the metabolic conversion between isocitrate and alpha-ketoglutarate (α-KG) in the TCA cycle. IDH2 mutation is an oncogenic event in acute myeloid leukemia (AML) due to the generation of 2-hydroxyglutarate. However, the role of wild-type IDH2 in AML remains unknown, despite patients with it suffer worse clinical outcome than those harboring mutant type.

Methods

IDH2 expression in AML cell lines and patient samples was evaluated by RT-qPCR, western blotting and database analyses. The role of wild-type IDH2 in AML cell survival and proliferation was tested using genetic knockdown and pharmacological inhibition in AML cells and animal models. LC–MS, GC–MS, isotope metabolic tracing, and molecular analyses were performed to reveal the underlying mechanisms.

Results

We found that wild-type IDH2 was overexpressed in AML and played a major role in promoting leukemia cell survival and proliferation in vitro and in vivo. Metabolomic analyses revealed an active IDH2-mediated reductive TCA cycle that promoted the conversion of α-KG to isocitrate/citrate to facilitate glutamine utilization for lipid synthesis in AML cells. Suppression of wild-type IDH2 by shRNA resulted in elevated α-KG and decreased isocitrate/citrate, leading to reduced lipid synthesis, a significant decrease in c-Myc downregulated by α-KG, and an inhibition of AML viability and proliferation. Importantly, pharmacological inhibition of IDH2 showed significant therapeutic effect in mice inoculated with AML cells with wt-IDH2 and induced a downregulation of C-MYC in vivo.

Conclusions

Wt-IDH2 is an essential molecule for AML cell survival and proliferation by promoting conversion of α-KG to isocitrate for lipid synthesis and by upregulating c-Myc expression and could be a potential therapeutic target in AML.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13045-022-01245-z.

IDH1/2 mutations in acute myeloid leukemia

The mutational and epigenetic landscape of acute myeloid leukemia (AML) has become increasingly well understood in recent years, informing on biological targets for precision medicine. Among the most notable findings was the recognition of mutational hot-spots in the isocitrate dehydrogenase (IDH) genes. In this review, we provide an overview on the IDH1/2 mutation landscape in Korean AML patients, and compare it with available public data. We also discuss the role of IDH1/2 mutations as biomarkers and drug targets. Taken together, occurrence of IDH1/2 mutations is becoming increasingly important in AML treatment, thus requiring thorough examination and follow-up throughout the clinical course of the disease.

Efficacy and Safety Profile of Ivosidenib in the Management of Patients with Acute Myeloid Leukemia (AML): An Update on the Emerging Evidence

The isocitrate dehydrogenase enzyme, catalyzing isocitrate conversion to α-ketoglutarate (αKG) in both the cell cytoplasm and mitochondria, contributes to the production of dihydronicotinamide-adenine dinucleotide phosphate (NADPH) as a reductive potential in various cellular processes. IDH1 gene mutations are revealed in up to 20% of the patients with acute myeloid leukemia (AML). A mutant IDH enzyme, existing in the cell cytoplasm and possessing neomorphic activity, converts αKG into oncometabolite R-2-hydroxyglutarate (R-2-HG) that accumulates in high amounts in the cell and inhibits αKG-dependent enzymes, including epigenetic regulators. The resultant alteration in gene expression and blockade of differentiation ultimately lead to leukemia development. Myeloid differentiation capacity can be restored by obstruction of the mutant enzyme, inducing substantial reduction in R-2-HG levels. Ivosidenib, a potent selective inhibitor of mutant IDH1, is a differentiating agent shown to be clinically effective in newly diagnosed AML (ND-AML) and relapsed/refractory (R/R) AML harboring this mutation. The drug is approved by the Food and Drug Administration (FDA) as a single-agent treatment for R/R AML. Significance of mutated IDH1 targeting and a potential role of ivosidenib in AML management, when used either as a single agent or as part of combination therapies, will be reviewed herein.

The implications of IDH mutations for cancer development and therapy

Mutations in the genes encoding the cytoplasmic and mitochondrial forms of isocitrate dehydrogenase (IDH1 and IDH2, respectively; collectively referred to as IDH) are frequently detected in cancers of various origins, including but not limited to acute myeloid leukaemia (20%), cholangiocarcinoma (20%), chondrosarcoma (80%) and glioma (80%). In all cases, neomorphic activity of the mutated enzyme leads to production of the oncometabolite D-2-hydroxyglutarate, which has profound cell-autonomous and non-cell-autonomous effects. The broad effects of IDH mutations on epigenetic, differentiation and metabolic programmes, together with their high prevalence across a variety of cancer types, early presence in tumorigenesis and uniform expression in tumour cells, make mutant IDH an ideal therapeutic target. Herein, we describe the current biological understanding of IDH mutations and the roles of mutant IDH in the various associated cancers. We also present the available preclinical and clinical data on various methods of targeting IDH-mutant cancers and discuss, based on the underlying pathogenesis of different IDH-mutated cancer types, whether the treatment approaches will converge or be context dependent.

A higher percentage of leukemic blasts with vacuoles predicts unfavorable outcomes in patients with acute myeloid leukemia

Cytoplasmic vacuoles, which are a morphological feature of dysplasia, can be observed under a microscope at initial diagnosis. Recently, this typical morphological feature has been found to be associated with impaired survival. To investigate the clinical significance of the grading of blasts with vacuoles in acute myeloid leukemia (AML), we retrospectively studied 152 patients newly diagnosed with non-M3 AML. The patients were categorized into three groups according to the percentage of blasts with vacuoles (>20 %, 11-20 %, 0-10 %). A high percentage of blasts with vacuoles (>20 %) was positively associated with the European Leukemia Net (2017-ELN) high-risk AML, a complex karyotype, TP53 and IDH1/2 mutations, and CD71 expression and negatively associated with the ELN low-risk category. Importantly, patients who had a higher percentage of blasts with vacuoles had a lower complete remission rate in response to first-cycle induction chemotherapy. The overall survival and event-free survival of patients who had a higher percentage of blasts with vacuoles were significantly shorter. Moreover, multivariate analysis showed that blast vacuolization was an independent high prognostic factor for AML. In conclusion, a higher percentage of leukemic blasts with vacuoles predicts worse outcomes in AML and may have potential as a prognostic marker.

Adverse Impact of DNA Methylation Regulatory Gene Mutations on the Prognosis of AML Patients in the 2017 ELN Favorable Risk Group, Particularly Those Defined by NPM1 Mutation

The 2017 ELN risk stratification has been widely adopted, but some studies have suggested the outcomes are heterogenous within the ELN risk groups and may be affected by other co-existing genetic mutations. This study evaluated the impact of DNA methylation regulatory gene (TET2, IDH1/2, DNMT3A, SETBP1) mutations (DMRGM) evaluated by NGS in the outcome of AML patients in each ELN risk group. A total of 114 patients were analyzed with a median follow-up of 12 months. Overall, 30.7% (35/114) of patients had DMRGM. DMRGM status had no impact on CR rate in each ELN risk group. The OS, however, was significantly shorter in patients with DMRGM compared to those without DMRGM (median OS: 12 vs. 33 months, p = 0.0053). Multivariate analysis showed DMRGM status was an independent unfavorable factor for OS (HR: 2.704, 95% CI: 1.451–5.041, p = 0.0017). The adverse OS impact of DMRGM was only observed in the ELN favorable group (7 months vs. not reached, p = 0.0001), but not in the intermediate or adverse group. Among the favorable group with DMRGM (n = 16), DMRGM occurred predominantly in cases with mutated NPM1 (15/16, or 93.8%). Our results suggest that DMRGM adversely impact the outcomes of ELN favorable group patients, particularly those with mutated NPM1. Further studies are warranted to confirm our observations.

Molecular mechanisms mediating relapse following ivosidenib monotherapy in IDH1-mutant relapsed or refractory AML

Isocitrate dehydrogenase (IDH) 1 and 2 mutations result in overproduction of D-2-hydroxyglutarate (2-HG) and impaired cellular differentiation. Ivosidenib, a targeted mutant IDH1 (mIDH1) enzyme inhibitor, can restore normal differentiation and results in clinical responses in a subset of patients with mIDH1 relapsed/refractory (R/R) acute myeloid leukemia (AML). We explored mechanisms of ivosidenib resistance in 174 patients with confirmed mIDH1 R/R AML from a phase 1 trial. Receptor tyrosine kinase (RTK) pathway mutations were associated with primary resistance to ivosidenib. Multiple mechanisms contributed to acquired resistance, particularly outgrowth of RTK pathway mutations and 2-HG-restoring mutations (second-site IDH1 mutations, IDH2 mutations). Observation of multiple concurrent mechanisms in individual patients underscores the complex biology of resistance and has important implications for rational combination therapy design. This trial was registered at www.clinicaltrials.gov as #NCT02074839.

Next-generation sequencing reveals gene mutations landscape and clonal evolution in patients with acute myeloid leukemia

OBJECTIVES

The study aims to understand geneome diversification and complexity that developed in Acute myeloid leukemia (AML).

METHODS

Next-generation sequencing (NGS) was used to identify the genetic profiles of 22 genes relevant to hematological malignancy in 204 patients with de novo non-M3 AML.

RESULTS

At time of initial diagnosis, at least one mutation was identified in 80.9% of patients (165/204). The most commonly mutated gene was NPM1 (22.1%), followed by ASXL1 (18.1%), TET2 (18.1%), IDH2 (15.7%), CEBPA (14.7%), FLT3-ITD (13.2%) and DNMT3A (11.8%). Mutations landscape analysis indicated several patterns of co-occurring and mutual exclusive gene mutations. Some correlation was observed between gene mutations and clinicohematological features. Multivariate analysis showed that age >60 years, karyotypes, IDH2 and KIT mutations were the independent unfavorable prognostic factors for OS; NPM1-mut/ FLT3-ITD-wt was independently correlated with prolonged OS; whereas the independent poor risk factors for RFS were karyotypes, high WBC and RUNX1 mutation. According to different genotype demonstrated by multivariate analysis, 163 patients with intermediate-risk cytogenetics were classified into three subgroups: patients with NPM1-mut/ FLT3-ITD-wt or biallelic CEBPA mutation as favorable risk, patients with KIT, IDH2, TP53 or NRAS mutations as unfavorable risk, and the remaining was the intermediate risk. We also obtain information of clonal evolution during leukemia progression by observing five patients who underwent repeat NGS at relapse in our cohort.

CONCLUSION

NGS techniques is a useful tool for discovering related gene mutations and clonal evolution in AML genomes, leading to novel targeted therapeutic approaches that could improve patients outcomes.

Tumor Microenvironmental Competitive Endogenous RNA Network and Immune Cells Act as Robust Prognostic Predictor of Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is malignant hematologic tumors with frequent recurrence and cause high mortality. Its fate is determined by abnormal intracellular competitive endogenous RNA (ceRNA) network and extracellular tumor microenvironment (TME). This study aims to build a ceRNA network related to AML TME to explore new prognostic and therapeutic targets. The RNA expression data of AML were obtained from The Cancer Genome Atlas (TCGA) database. First, we used the ESTIMATE algorithm to calculate the immune cells and stromal cells infiltration scores in the TME and found that all scores were highly correlated with AML’s prognostic characteristics. Subsequently, differentially expressed mRNAs and lncRNAs between high and low score groups were identified to construct a TME-related ceRNA network. Further, the Cox-lasso survival model was employed to screen out the hub prognostic ceRNA network composed of two mRNAs (EPB41L3, COL2A1), three miRNAs (hsa-mir-26a-5p, hsa-mir-148b-3p, hsa-mir-148a-3p), and two lncRNAs (CYP1B1-AS1, C9orf106), and construct nomograms. Finally, we used CIBERSORT algorithm and Kaplan-Meier survival analysis to identify the prognostic TME immune cells and found that naive B cells, M2-type macrophages, and helper follicular T cells were related to prognosis, and the hub ceRNAs were highly correlated with immune cell infiltration. This study provided a new perspective to elucidate how TME regulates AML process and put forward the new therapy strategies combining targeting tumor cells with disintegrating TME.

[Prognostic significance of different IDH mutations and accompanying gene mutations in patients with acute myeloid leukemia]

目的

探讨IDH不同突变亚型及伴发不同基因突变在非M₃型急性髓系白血病（AML）患者中的预后意义。

方法

采用二代测序技术检测2016年6月至2018年12月就诊于郑州大学第一附属医院的389例AML患者的22种基因突变情况，通过Kaplan-Meier法及Cox回归模型分析影响预后的因素。

结果

389例AML患者中，IDH1及IDH2的突变率分别为6.2%、8.7%，未发现IDH1与IDH2共突变的情况。IDH2突变型患者年龄偏大、骨髓原始细胞比例高、正常核型多见、常合并RUNX1突变及SRSF2突变。单因素方差分析发现，IDH1突变型组较野生型组的中位总生存（OS）及无进展生存（PFS）时间明显缩短（P值均<0.05）；IDH2突变作为一个单变量对预后无显著影响，不同突变位点对预后的影响不同，IDH2R140突变对预后无显著影响，IDH2R172突变型患者较IDH2野生型患者完全缓解（CR）率明显减低、中位OS及PFS时间明显缩短（P值均<0.05）。在正常核型或年龄≥50岁的患者中，IDH不同突变亚型显示出同样的预后意义。74.1%（43/58）IDH突变患者同时携带其他基因突变，伴发基因突变数目对患者的预后无显著影响，IDH突变患者中伴NPM1突变者的CR率明显高于不伴NPM1突变者（81.8%对36.4%，P＝0.014），伴DNMT3A突变者的中位OS时间短于不伴DNMT3A突变者[4.0（95%CI 3.8～4.2）个月对6.3（95%CI 2.4～10.2）个月，P＝0.041]。多因素分析显示：年龄≥60岁、WBC≥100×10⁹/L是影响患者OS及PFS的独立危险因素，2个疗程内CR、造血干细胞移植是影响患者OS及PFS的独立有利因素。

结论

在AML（非M₃型）患者中，IDH基因突变常与其他基因突变共存，IDH不同突变亚型及伴发基因突变显示出不同的预后意义。

Alterations to DNMT3A in Hematologic Malignancies

In the last decade, large-scale genomic studies in patients with hematologic malignancies identified recurrent somatic alterations in epigenetic modifier genes. Among these, the de novo DNA methyltransferase DNMT3A has emerged as one of the most frequently mutated genes in adult myeloid as well as lymphoid malignancies and in clonal hematopoiesis. In this review, we discuss recent advances in our understanding of the biochemical and structural consequences of DNMT3A mutations on DNA methylation catalysis and binding interactions and summarize their effects on epigenetic patterns and gene expression changes implicated in the pathogenesis of hematologic malignancies. We then review the role played by mutant DNMT3A in clonal hematopoiesis, accompanied by its effect on immune cell function and inflammatory responses. Finally, we discuss how this knowledge informs therapeutic approaches for hematologic malignancies with mutant DNMT3A.

Clinical characteristics and outcomes in patients with acute myeloid leukemia with concurrent FLT3-ITD and IDH mutations

BACKGROUND

Isocitrate dehydrogenase (IDH1 and IDH2) mutations commonly co-occur with FMS-like tyrosine kinase 3 (FLT3) mutations in patients with acute myeloid leukemia (AML).

METHODS

The authors reviewed cases of patients with FLT3-internal tandem duplication (FLT3-ITD)-mutated AML with concurrent IDH mutations diagnosed between January 2011 and December 2018.

RESULTS

A total of 91 patients with FLT3-ITD and IDH1 or IDH2 "double-mutated" AML were identified; 36 patients had concurrent FLT3-ITD/IDH1 mutations (18 in the frontline and 18 in the recurrent and/or refractory [R/R] setting) and 55 patients had concurrent FLT3-ITD/IDH2 mutations (37 in the frontline and 18 in the R/R setting). FLT3 and/or IDH inhibitors (FLT3Is and/or IDHIs) were given as a single agent or in combination with cytotoxic chemotherapy (CCT) or low-intensity therapy (LIT). Rates of complete remission (CR) plus CR with incomplete count recovery (CRi) with the use of CCT and FLT3Is were 100% and 64%, respectively, in patients in the frontline and R/R settings. CCT with IDHIs was given in 2 frontline patients and both achieved a CR. LIT with FLT3Is in the frontline and R/R settings demonstrated CR and CRi rates of 67% and 28%, respectively. Single-agent FLT3Is and IDHIs demonstrated limited activity with a CR and/or CRi rate of 14% in patients with disease in the R/R setting.

CONCLUSIONS

The combination of FLT3I-based therapy with CCT or LIT appeared to be effective in both the frontline and R/R settings among patients with FLT3-ITD/IDH co-mutated disease. Fewer patients with double-mutated disease received CCT or LIT with IDH1/2 inhibitor in the frontline setting; however, high response rates also were noted with this approach.

LAY SUMMARY

The prognostic influence of FMS-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD) and isocitrate dehydrogenase (IDH) co-mutation status on outcomes in patients with acute myeloid leukemia receiving an FLT3 inhibitor, non-FLT3/IDH inhibitor-based regimens, or an IDH inhibitor is unclear. This is an important clinical question because multiple targeted therapies for FLT3 and IDH1/2 mutations have become available. The results of the current study demonstrated that a combination of a FLT3 inhibitor with cytotoxic chemotherapy or low-intensity therapy appears to be an effective approach in patients with FLT3-ITD/IDH co-mutated disease in both the frontline and recurrent and/or refractory settings. Fewer dual-mutated patients received cytotoxic chemotherapy or low-intensity therapy with an IDH1/2 inhibitor in the frontline setting; however, excellent responses also were observed with this approach.

IDH1/2 mutations in acute myeloid leukemia patients and risk of coronary artery disease and cardiac dysfunction-a retrospective propensity score analysis

Clonal hematopoiesis of indeterminate potential (CHIP) is linked to leukemia gene mutations and associates with an increased risk for coronary artery disease and poor prognosis in ischemic cardiomyopathy. Two recurrently mutated genes in CHIP and adult acute myeloid leukemia (AML) encode for isocitrate dehydrogenases 1 and 2 (IDH1 and IDH2). Global expression of mutant IDH2 in transgenic mice-induced dilated cardiomyopathy and muscular dystrophy. In this retrospective observational study, we investigated whether mutant IDH1/2 predisposes to cardiovascular disease in AML patients. Among 363 AML patients, IDH1 and IDH2 mutations were detected in 26 (7.2%) and 39 patients (10.7%), respectively. Mutant IDH1 patients exhibited a significantly higher prevalence of coronary artery disease (26.1% vs. 6.4%, p = 0.002). Applying inverse probability-weighting analysis, patients with IDH1/2 mutations had a higher risk for a declining cardiac function during AML treatment compared to IDH1/2 wild type patients [left ventricular ejection fraction pretreatment compared to 10 months after diagnosis: 59.2% to 41.9% (p < 0.001) vs 58.5% to 55.4% (p = 0.27), respectively]. Mechanistically, RNA sequencing and immunostaining in hiPS-derived cardiomyocytes indicated that the oncometabolite R-2HG exacerbated doxorubicin mediated cardiotoxicity. Evaluation of IDH1/2 mutation status may therefore help identifying AML patients at risk for cardiovascular complications during cytotoxic treatment.

Isocitrate Dehydrogenase Mutations in Myelodysplastic Syndromes and in Acute Myeloid Leukemias

Acute myeloid leukemia (AML) is a heterogeneous disease generated by the acquisition of multiple genetic and epigenetic aberrations which impair the proliferation and differentiation of hematopoietic progenitors and precursors. In the last years, there has been a dramatic improvement in the understanding of the molecular alterations driving cellular signaling and biochemical changes determining the survival advantage, stimulation of proliferation, and impairment of cellular differentiation of leukemic cells. These molecular alterations influence clinical outcomes and provide potential targets for drug development. Among these alterations, an important role is played by two mutant enzymes of the citric acid cycle, isocitrate dehydrogenase (IDH), IDH1 and IDH2, occurring in about 20% of AMLs, which leads to the production of an oncogenic metabolite R-2-hydroxy-glutarate (R-2-HG); this causes a DNA hypermethylation and an inhibition of hematopoietic stem cell differentiation. IDH mutations differentially affect prognosis of AML patients following the location of the mutation and other co-occurring genomic abnormalities. Recently, the development of novel therapies based on the specific targeting of mutant IDH may contribute to new effective treatments of these patients. In this review, we will provide a detailed analysis of the biological, clinical, and therapeutic implications of IDH mutations.

Acute myeloid leukemia sensitivity to metabolic inhibitors: glycolysis showed to be a better therapeutic target

Cancer cells alter their metabolism by switching from glycolysis to oxidative phosphorylation (OXPHOS), regardless of oxygen availability. Metabolism may be a molecular target in acute myeloid leukemia (AML), where mutations in metabolic genes have been described. This study evaluated glycolysis and OXPHOS as therapeutic targets. The sensitivity to 2-deoxy-D-glucose (2-DG; glycolysis inhibitor) and oligomycin (OXPHOS inhibitor) was tested in six AML cell lines (HEL, HL-60, K-562, KG-1, NB-4, THP-1). These cells were characterized for IDH1/2 exon 4 mutations, reactive oxygen species, and mitochondrial membrane potential. Metabolic activity was assessed by resazurin assay, whereas cell death and cell cycle were assessed by flow cytometry. Glucose uptake and metabolism-related gene expression were analyzed by ¹⁸F-FDG and RT-PCR/qPCR, respectively. No IDH1/2 exon 4 mutations were detected. HEL cells had the highest ¹⁸F-FDG uptake and peroxides/superoxide anion levels, whereas THP-1 showed the lowest. 2-DG reduced metabolic activity in all cell lines with HEL, KG-1, and NB-4 being the most sensitive cells. Oligomycin decreased metabolic activity in a cell line-dependent manner, the THP-1 resistant and HL-60 being the most sensitive. Both inhibitors induced apoptosis and cell cycle arrest in a cell line- and compound-dependent manner. 2-DG decreased ¹⁸F-FDG uptake in HEL, HL-60, KG-1, and NB-4, while oligomycin increased the uptake in K-562. Metabolism gene expression had different responses to treatments. In conclusion, HEL and KG-1 show to be more glycolytic, whereas HL-60 was more OXPHOS dependent. Results suggest that AML cells reprogram their metabolism to overcome OXPHOS inhibition suggesting that glycolysis may be a better therapeutic target.

Ivosidenib induces deep durable remissions in patients with newly diagnosed IDH1-mutant acute myeloid leukemia

Ivosidenib (AG-120) is an oral, targeted agent that suppresses production of the oncometabolite 2-hydroxyglutarate via inhibition of the mutant isocitrate dehydrogenase 1 (IDH1; mIDH1) enzyme. From a phase 1 study of 258 patients with IDH1-mutant hematologic malignancies, we report results for 34 patients with newly diagnosed acute myeloid leukemia (AML) ineligible for standard therapy who received 500 mg ivosidenib daily. Median age was 76.5 years, 26 patients (76%) had secondary AML, and 16 (47%) had received ≥1 hypomethylating agent for an antecedent hematologic disorder. The most common all-grade adverse events were diarrhea (n = 18; 53%), fatigue (n = 16; 47%), nausea (n = 13; 38%), and decreased appetite (n = 12; 35%). Differentiation syndrome was reported in 6 patients (18%) (grade ≥3 in 3 [9%]) and did not require treatment discontinuation. Complete remission (CR) plus CR with partial hematologic recovery (CRh) rate was 42.4% (95% confidence interval [CI], 25.5% to 60.8%); CR 30.3% (95% CI, 15.6% to 48.7%). Median durations of CR+CRh and CR were not reached, with 95% CI lower bounds of 4.6 and 4.2 months, respectively; 61.5% and 77.8% of patients remained in remission at 1 year. With median follow-up of 23.5 months (range, 0.6-40.9 months), median overall survival was 12.6 months (95% CI, 4.5-25.7). Of 21 transfusion-dependent patients (63.6%) at baseline, 9 (42.9%) became transfusion independent. IDH1 mutation clearance was seen in 9/14 patients achieving CR+CRh (5/10 CR; 4/4 CRh). Ivosidenib monotherapy was well-tolerated and induced durable remissions and transfusion independence in patients with newly diagnosed AML. This trial was registered at www.clinicaltrials.gov as #NCT02074839.

Inhibitory effects of voriconazole, itraconazole and fluconazole on the pharmacokinetic profiles of ivosidenib in rats by UHPLC-MS/MS

Ivosidenib, as an oral mutant isocitrate dehydrogenase 1 (mIDH1) inhibitor, was awarded approval in the USA for the targeted therapy of relapsed or refractory acute myeloid leukemia (AML) in adult patients, who also had a susceptible enzyme to mIDH1. The aim of our present study was to develop and validate an accurate and fast assay based on the ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) technique for the quantification of ivosidenib in plasma and to investigate the possible effects of different CYP3A4 inhibitors (voriconazole, itraconazole and fluconazole) on ivosidenib metabolism in rats. After the fast protein crash with acetonitrile, chromatographic separation of ivosidenib and erlotinib (used as the internal standard in this experiment, IS) was accomplished using an Acquity BEH C18 (2.1 mm × 50 mm, 1.7 μm) column, and detection of the analyte was also performed using a Xevo TQ-S triple quadrupole tandem mass spectrometer in the positive ion electrospray ionization (ESI) interface. The assay showed enough linearity over a 0.5-6000 ng/mL calibration range. The application of the validated bioanalytical method based on the UHPLC-MS/MS technique was further successfully exhibited in an animal study of the drug-drug interaction between ivosidenib (50 mg/kg) and voriconazole (20 mg/kg)/itraconazole (20 mg/kg)/fluconazole (20 mg/kg) in rats. Voriconazole, itraconazole and fluconazole increased the exposure of ivosidenib in plasma by different degrees and also had a potential inhibitory effect on the metabolism of ivosidenib. Thus, a dose reduction or interruption of ivosidenib may be important to guide the practice of clinical medicine.

Association between CYP2B6 polymorphism and acute leukemia in a Han population of Northwest China

Background

The aim of this study was to investigate potential associations between CYP2B6 c.516G>T polymorphism and the occurrence and prognosis of acute leukemias (AL) in the Han population of Northwest China.

Methods

The CYP2B6 gene polymorphism was analyzed by PCR‐RFLP and Sanger DNA sequencing in 126 patients with AL and 161 healthy controls.

Results

Compared with controls, there were significantly higher frequencies of GT and TT genotypes and T alleles in AL patients (p < .05), particularly in fusion gene‐positive AL patients. There was no significant difference in CYP2B6 polymorphic genotypes and T alleles between AL patients with complete remission after the first course of chemotherapy and controls (p > .05), while the frequencies in AL patients with partial remission and no remission were significantly higher. The CYP2B6 allele frequency in Han Chinese in Northwest China was significantly different to that reported in Han Chinese and other ethnic minorities in southern China, Uygur Chinese, Vietnamese, African, German, British, Spanish, Turkish, and Argentinian populations; however, there was no significant difference compared with allele frequencies reported in Tibetan and Mongolian Chinese, Japanese, Korean, and American populations.

Conclusion

Our findings show a strong correlation of the CYP2B6 c.516G>T polymorphism in the Han population of Northwest China with AL, especially fusion gene‐positive AL, and indicate a poor prognosis after the first course of chemotherapy. Our findings also implicate the T allele in AL susceptibility and indicate the existence of racial and geographical differences in allele frequencies of CYP2B6 c.516G>T polymorphism.

IDH Mutations in AML Patients; A higher Association with Intermediate Risk Cytogenetics

Objective:

IDH mutations diversely affect the prognosis of cyogenetically normal acute myeloid leukemia (CN-AML) adult patients. The aim of this study is to assess the frequency of IDH mutations and to evaluate its role in AML prognosis.

Methods:

We have analyzed IDH1 and 2 mutations using High Resolution Melting curve analysis (HRM) in 70 denovo AML patients.

Results:

The median age of AML patients is 40 years (16-75). Incidence of IDH mutations is 10/70 (14.3%); 2 (2.9%) IDH1 mutant and 8 (11.4%) IDH2 mutant. Median PB blasts of mutant IDH patients was 67.5% (25-96) vs. 44% (0-98) for wild type (p=0.065). Eight/10 (80%) mutant IDH patients had B.M blasts ≥50% vs. 2/10 (20%) <50% (p<0.001) and were classified as intermediate risk cytogenetics (p=0.020) with wild FLT3-ITD (p=0.001). Ten/10 (100%) mutant IDH patients showed wild NPM1 (p=0.049). Median OS of mutant IDH in the intermediate risk cytogenetics was 1.8 years (0.7-3.1) vs. 3.1 years (1.1-5.5) for wild IDH (p=0.05).

Conclusion:

IDH mutation is mainly associated with intermediate risk AML and when integrated in this specific subgroup displays a lower survival and can be considered an additional integrated molecular risk marker for AML prognosis.

The face of remission induction

Acute myeloid leukaemia (AML) is a heterogeneous disease in which prognosis is determined by cytogenetic and molecular aberrations as well as patient-related factors, including age, prior haematologic disorders, and comorbidities. Despite the diverse disease biology, the standard of care for remission induction therapy has changed very little since its inception in 1973. Next generation sequencing has helped to increase our knowledge of the disease pathogenesis, allowing us to develop targeted and possibly more effective treatment options. Seven new agents have been approved for the treatment of AML since 2017, all of which are directed toward a specific molecular subtype or patient population. With the advent of these therapies, a more optimal, patient-specific approach rather than the historical 'one-size fits all' model can be utilised. This review will discuss the role of these novel therapies in the remission induction setting.

Isocitrate dehydrogenase inhibitors in acute myeloid leukemia

Isocitrate dehydrogenase (IDH) is a key enzyme involved in the conversion of isocitrate to α-ketoglutarate (α-KG) in the tricarboxylic acid (TCA) cycle. IDH mutation produces a neomorphic enzyme, which can lead to the abnormal accumulation of R-2-HG and promotes leukemogenesis. IDH mutation occurs in 20% of acute myeloid leukemia (AML) patients, mainly including IDH1 R132, IDH2 R140, and IDH2 R172. Different mutant isoforms have different prognostic values. In recent years, IDH inhibitors have shown good clinical response in AML patients. Hence, enasidenib and ivosidenib, the IDH2 and IDH1 inhibitors developed by Agios Pharmaceuticals, have been approved by the Food and Drug Administration on 1 August 2017 and 20 July 2018 for the treatment of adult relapsed or refractory (R/R) AML with IDH2 and IDH1 mutations, respectively. IDH inhibitor monotherapy for R/R AML is efficacious and safe; however, there are problems, such as primary or acquired resistance. Clinical trials of IDH inhibitors combined with hypomethylating agents or standard chemotherapy for the treatment of R/R AML or newly diagnosed AML, as well as in post hematopoietic stem cell transplantation as maintenance therapy, are ongoing. This article summarizes the use of IDH inhibitors in AML with IDH mutations.

Targeting Metabolic Reprogramming in Acute Myeloid Leukemia

The cancer metabolic reprogramming allows the maintenance of tumor proliferation, expansion and survival by altering key bioenergetics, biosynthetic and redox functions to meet the higher demands of tumor cells. In addition, several metabolites are also needed to perform signaling functions that further promote tumor growth and progression. These metabolic alterations have been exploited in different cancers, including acute myeloid leukemia, as novel therapeutic strategies both in preclinical models and clinical trials. Here, we review the complexity of acute myeloid leukemia (AML) metabolism and discuss how therapies targeting different aspects of cellular metabolism have demonstrated efficacy and how they provide a therapeutic window that should be explored to target the metabolic requirements of AML cells.

Epigenetic modifier gene mutations-positive AML patients with intermediate-risk karyotypes benefit from decitabine with CAG regimen

It remains unclear whether there is a relationship between therapeutic effects of hypomethylating agents (HMAs) and epigenetic modifier gene mutations (EMMs) in patients with cytogenetically intermediate-risk acute myeloid leukemia (IR-AML). Based on targeted-capture sequencing, we retrospectively analyzed the correlation between EMMs and prognosis in 83 IR-AML patients treated with decitabine in combination with cytarabine, aclarubicin hydrochloride and granulocyte colony-stimulating factor (DCAG, n = 35) or "7 + 3" induction regimens (n = 48). In the multivariate analyses, EMM (+) patients did not show any statistically significant difference in remission rates from EMM (-) patients in the DCAG group (p > 0.05), but achieved inferior complete remission (CR; p = 0.03) and overall remission rates (ORR; p = 0.04) after the first course of standard induction regimens (p < 0.05). In the EMM (-) cohort, the DCAG group showed the tendency of adverse total CR (p = 0.06). Besides, DCAG group with EMMs achieved the best survival outcome independent of baseline characteristics, whereas it was opposite in EMM (+) patients receiving standard induction regimens (p < 0.05). Additionally, in the EMM (+) cohort, the survival rate of isolated DCAG group was statistically similar to that of the combination of standard chemotherapies and allogeneic hematopoietic stem cell transplantation (allo-HSCT) (p > 0.40), whereas patients who received only standard regimens had the worst survival rate (0.0%, p < 0.01). It can be concluded that the EMMs might be regarded as the potentially predictive biomarkers of better response to DCAG in IR-AML patients.