FLT3-ITD Mutations Research Articles

New Combination Regimens vs. Fludarabine, Cytarabine, and Idarubicin in the Treatment of Intermediate- or Low-Risk Nucleophosmin-1-Mutated Acute Myeloid Leukemia: A Retrospective Analysis from 7 Italian Centers

Background: Nucleophosmin-1 (NPM1) mutation accounts for 30% of acute myeloid leukemia (AML) cases and defines either low- or intermediate-risk AML, depending on FLT3-ITD mutation. New combination regimens (NCRs), adding midostaurin and gemtuzumab ozogamicin (GO) to the 3 + 7 scheme, are commonly used, though there are no data that compare NCRs with intensive induction chemotherapy. Methods: To evaluate the efficacy and safety of NCRs and FLAI in NPM1+ AML, we retrospectively analyzed 125 patients treated with FLAI (n = 53) or NCRs (n = 72) at seven Italian Centers. Results: The median age was 61 years and 51/125 (41%) were FLT3-ITD+. The complete remission (CR) rate was 77%, slightly better with NCRs (83% vs. 68%; p = 0.054). NCRs yielded a superior median overall survival (OS) (not reached (NR) vs. 27.3 months; p = 0.002), though the median event-free survival (EFS) was similar (NR vs. 20.5 months; p = 0.07). In low-risk AML, CR was higher in NCRs (94% vs. 72%, p = 0.02), as were median OS (NR vs. 41.6 months; p = 0.0002) and EFS (NR vs. 17.8 months; p = 0.0085). In intermediate-risk AML (FLT3-ITD+), there were no differences in CR (60% vs. 71%; p = 0.5), OS (p = 0.27), or EFS (p = 0.86); only allogeneic transplantation improved OS (NR vs. 13.4 months; p = 0.005), regardless of induction regimen. The safety profile was similar, except for delayed platelet recovery with FLAI (22 vs. 18 days; p = 0.0024) and higher-grade II–IV gastrointestinal toxicity with NCRs (43% vs. 18.8%; p = 0.0066). Conclusions: Our data suggest the superiority of NCRs over FLAI in low-risk patients, while all outcomes were comparable in intermediate-risk patients, a setting in which only transplants positively impacted on survival.

Characteristics, outcomes and treatment patterns in acute myeloid leukemia patients 60 years or older in Colombia: a RENEHOC-PETHEMA study.

There is a limited information available on the clinical characteristics, treatment patterns and outcomes on older patients diagnosed with Acute Myeloid Leukemia (AML) in Latin-America. This multicenter retrospective study analyzed 269 patients over 60 years of age diagnosed with AML in Colombia, using data from RENEHOC-PETHEMA registry, from 2009 to 2023. The median age at diagnosis was 70 years (Range:60-98), 55% were men, 61% had an ECOG < 2, and 75.5% had de novo AML. FLT3-ITD or NPM1 mutations were performed in 23.4% and 15.6% patients, and detected in 14.3% and 16.7% of cases, respectively. Treatment included intensive chemotherapy (IC) (36.8%), Low-Intensity Regimen Based on Low-Dose Cytarabine (LDAC-based) (12.6%), hypomethylating agents (HMAs, with/without venetoclax) (35.3%), and supportive care (15.2%). The overall survival (OS) rate was 35.2% at 1 year and 5.6% at 5 years (13.7% for IC, 9.4% for LDAC-based, and 0% for other treatments); with median OS of 8.2 months (10.6 months after IC, 8.8 months after non-IC, 8.9 months after azacitidine/decitabine, 8.2 months after azacitidine-venetoclax, and 1.9 months with supportive care). Only 1.5% of patients underwent a transplant in the first line. The Leukemia-free survival (LFS) rate was 45.8% at 1-year and 13.7% at 5-years (22.4% for IC, 9.4% and 0% for other treatments); with median LFS of 9.5 months (17.3 months after IC, 7.4 months after LDAC-based, and 10.8 months after HMA). This study provides new insights into the management of patients in Colombia, highlighting the need for a highly individualized approach in treating AML in elderly patients.

Measurable residual disease and posttransplantation gilteritinib maintenance for patients with FLT3-ITD-mutated AML.

BMT CTN 1506 ("MORPHO"; NCT02997202) was a randomized phase 3 study of gilteritinib compared to placebo as maintenance therapy after hematopoietic stem cell transplantation (HCT) for patients with FLT3-ITD-mutated acute myeloid leukemia (AML). A key secondary endpoint was to determine the impact on survival of pre- and/or post-HCT measurable residual disease (MRD), as determined using a highly sensitive assay for FLT3-ITD mutations. Generally, gilteritinib maintenance therapy was associated with improved relapse-free survival (RFS) for participants with detectable peri-HCT MRD, whereas no benefit was evident for those lacking detectable MRD. We conducted a post-hoc analysis of the data and found that the level of MRD detected with this approach correlated remarkably with RFS and relapse risk, and that MRD detectable at any level negatively impacted RFS. In the placebo arm, 42.2% of participants with detectable FLT3-ITD MRD relapsed compared to 13.4% of those without detectable MRD. We found that 14.8% of participants had multiple FLT3-ITD clones detected as MRD and had worse survival irrespective of treatment arm. Finally, we examined the kinetics of FLT3-ITD clonal relapse or eradication and found that participants on the placebo arm with detectable MRD relapsed rapidly after HCT, often within a few weeks. MRD-positive participants on the gilteritinib arm relapsed either with FLT3 wild type clones (as assessed by capillary electrophoresis), after cessation of gilteritinib with persistent MRD, or on progression of multi-clonal disease. These data demonstrate the potential of using FLT3-ITD MRD to guide therapy with gilteritinib for this subtype of AML.

Disease characteristics and outcomes of acute myeloid leukemia in germline RUNX1 deficiency (Familial Platelet Disorder with associated Myeloid Malignancy).

Familial Platelet Disorder with associated Myeloid Malignancy (FPDMM, FPD/AML, RUNX1-FPD), caused by monoallelic deleterious germline RUNX1 variants, is characterized by bleeding diathesis and predisposition for hematologic malignancies, particularly myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). Clinical data on FPDMM-associated AML (FPDMM-AML) are limited, complicating evidence-based clinical decision-making. Here, we present retrospective genetic and clinical data of the largest cohort of FPDMM patients reported to date. We describe 159 European patients (from 94 families) of whom 134 were evaluable for the development of malignant disease. Sixty developed a hematologic malignancy (44.8%), most frequently AML (36/134, 26.9%) or MDS (18/134, 13.4%). Somatic alterations of RUNX1 by gene mutation (48%) and chromosome 21 aberrations (14.3%) were the most common somatic genetic aberrations in FPDMM-AML, followed by FLT3-ITD mutations (24.1%). Somatic RUNX1 and FLT3-ITD mutations were not detected in FPDMM-associated MDS, suggesting important contributions to leukemic transformation. Remission-induction chemotherapy resulted in complete remission in 80% of FPDMM-AML patients with a 5-year overall survival (OS) of 50.4%. Survival outcome was non-inferior compared to a large cohort of newly diagnosed adult RUNX1-mutated AML (5-year OS 36.6%, p = 0.5), with relatively infrequent concurrent adverse risk somatic aberrations (ASXL1 mutation, monosomal karyotype, monosomy 5/del 5q) in FPDMM-AML. Collectively, data support the notion that step-wise leukemic evolution in FPDMM is associated with distinct genetic events and indicate that a substantial subset of FPDMM-AML patients achieves prolonged survival with conventional AML treatment, including allogeneic stem cell transplant. These findings are anticipated to inform personalized clinical decision-making in this rare disorder.

MECOM and BAALC gene expression profiles in Egyptian patients with acute myeloid leukemia by next generation sequencing

ABSTRACT Background Acute myeloid leukemia (AML) is a challenging heterogenous hematologic malignancy characterized by suboptimal outcomes. Genetic characterization of AML enhanced the understanding of individualized patient’s risk and led to the development of new therapeutic strategies. Gene expression analysis facilitates detection of new diagnostic, prognostic, and predictive biomarkers. This necessitates the expansion of diagnostic testing with higher throughput technologies, such as targeted next-generation sequencing (NGS). Objectives To study the expression profiles of MECOM and BAALC genes in a cohort of newly diagnosed Egyptian AML patients via Oncomine Myeloid Research assay (OMA) by NGS technology in addition to studying their potential prognostic role and impact on overall survival (OS). Methods The OMA was used to evaluate the expression levels of MECOM and BAALC genes and five control genes (FBXW2, PUM1, TRIM27, PSMB2, and EIF2B1), in twenty-four newly diagnosed AML patients by NGS technology, using RNA extracted from bone marrow aspirate (BMA) specimens. Results Gene expression analysis of MECOM and BAALC genes revealed that MECOM overexpression was significantly associated with the presence of lymphadenopathy and the high MECOM median expression level was significantly associated with lower hemoglobin concentrations at presentation. BAALC overexpression showed significant associations with the presence of CD34, the presence of wild type NPM1 mutation, and the absence of FLT3-ITD mutations. However, BAALC underexpression was significantly associated with normal cytogenetics, while its overexpression was associated with adverse and favorable cytogenetics, with a statistically significant difference between them (p = 0.049)*. Statistically significant positive correlation was found between BAALC expression levels and postinduction BM blast percentages. Among these two genes, only high BAALC expression had significantly shorter OS in AML patients based on the log rank test (p = 0.037)*. Conclusion BAALC expression might be a specific molecular marker used for the assessment of prognosis and OS in AML patients and might be used in the future as targeted therapy in AML, aiming to improve patient outcomes and OS.

Discovery of 3-amide-pyrimidine-based derivatives as potential fms-like tyrosine receptor kinase 3 (FLT3) inhibitors for treating acute myelogenous leukemia.

FLT3-ITD and TKD mutants play a central role in acute myeloid leukemia (AML), making FLT3 an attractive target for AML treatment. To discover next-generation FLT3 inhibitors and gather additional structure-activity relationship (SAR) information, we performed structural modifications of G-749 (denfivontinib) utilizing structure simplification and scaffold hopping strategies. Among these derivatives, MY-10 exhibited the most potent and selective inhibition of MV4-11 cell proliferation, demonstrating potent inhibitory activity against FLT3-ITD (IC50 = 6.5 nM) and FLT3-D835Y (IC50 = 10.3 nM) mutants. Notably, MY-10 exhibited no inhibitory activity against c-KIT kinase (IC50 > 100 μM). Mechanistic studies revealed that MY-10 arrested the cell cycle at the G0/G1 phase and efficiently induced apoptosis. Furthermore, it significantly reduced reactive oxygen species (ROS) production and mitochondrial membrane potential (MMP), and strongly inhibited FLT3-mediated signaling pathways. These findings, along with the obtained SAR information, provide valuable insights for the further development of FLT3 inhibitors.

Prognostic value of myeloid-derived suppressor-like cells in acute myeloid leukemia: insights from immunophenotyping and clinical correlations.

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population that acts on both innate and adaptive immunity, fostering immune escape in tumors and contributing to cancer progression. Despite the lack of definitive markers for immunophenotyping MDSCs, particularly the polymorphonuclear (PMN-MDSC) subset, these cells seem to play a crucial role in acute myeloid leukemia (AML) patients' prognosis. Additionally, the maturation stage of MDSCs remains a subject of debate and is largely unknown within the AML context. In this study, we conducted a retrospective analysis of flow cytometry immunophenotyping data obtained at the diagnosis of AML patients. We explored how the enrichment of neutrophil maturation stages, the frequency of PMN-MDSC-like cells and monocytic MDSC-like population (M-MDSC-like), and the ratios of MDSC-like cells to T lymphocytes correlate with relevant prognostic indicators. Our findings revealed that CD45+CD33lowHLA-DR-CD36+ PMN-MDSC-like cells and mature CD13+CD11b+CD10+ neutrophils correlate poor survival in AML patients. Furthermore, PMN-MDSC-like cells, and their ratio to T lymphocytes, are elevated in patients with adverse-risk stratification. Similarly, the M-MDSC-like population is increased in FLT3-ITD mutation carrier patients. Notably, we observed confirmational evidence of CD36 relevance in the AML context, which has emerged recently as a potential marker for PMN-MDSCs. Our study highlights significant findings associating increased MDSC-like subsets and poor prognostic factors in AML.

All-trans retinoic acid potentiates cell death induced by quizartinib in acute myeloid leukemia with FLT3-ITD mutations.

Acute myeloid leukemia (AML) with FLT3-ITD mutation represents a quarter of AML patients and is associated with high relapse rate and dismal prognosis. FLT3 tyrosine kinase inhibitors (TKIs) were developed in order to target this genetic alteration and among these TKIs, AC220 (quizartinib) combined with chemotherapy has already shown an increased overall survival for patients with AML with FLT3-ITD mutation. Even though this increase in overall survival was significant, it remains discrete, and relapse rate is still high, so there is an unmet medical need. All-trans retinoic acid (ATRA) is well known for its effectiveness in acute promyelocytic leukemia (APL) treatment and has already been shown to have synergistic effects combined with another TKI, sorafenib. In this study, quizartinib, a more potent FLT3-TKI, was tested in combination with ATRA in the AML FLT3-ITD positive cell lines MOLM-13 and MV4-11. ATRA has effectively improved AC220 induced cell death via caspase activation. In addition, ATRA in combination with AC220 treatment notably enhanced BECN1 cleavage compared to AC220 treatment alone. Finally, in a xenotransplantation model ATRA plus AC220 was more efficient to reduce the leukemic burden than monotherapy with ATRA or AC220. Taken together, our results are a proof of the concept that ATRA and AC220 have synergistic anti-leukemic effects.

Case report: Identification of a novel TOR1AIP2::ETV6 transcript with FLT3-ITD mutation in acute myeloid leukemia progressed from myelodysplastic syndrome

Acute myeloid leukemia (AML), which is most common in adults, is a challenging hematological malignancy. The occurrence and the progression of AML are often accompanied by various gene fusions and/or mutations. Herein, we report the first case of a TOR1AIP2::ETV6 fusion transcript with a translocation of t(1;12)(q25;p13) in AML progressed from myelodysplastic syndrome (MDS) combined with an FLT3-ITD (internal tandem duplication) mutation. Further studies should focus on the biological functions of these novel chimeric products in disease onset and progression, as well as their potential as monitoring markers in disease regression.

Allogeneic hematopoietic stem cell transplantation could overcome the poor prognosis of DNMT3AmutNPM1mutFLT3-ITDmut in acute myeloid leukemia: real-world multicenter analysis in China.

The cooccurrence of NPM1, FLT3-ITD, and DNMT3A mutations (i.e., triple mutation) is related to dismal prognosis in patients with acute myeloid leukemia (AML) receiving chemotherapy alone. In this multicenter retrospective cohort study, we aimed to identify whether allogeneic hematopoietic stem cell transplantation (allo-HSCT) could overcome the poor prognosis of DNMT3AmutNPM1mutFLT3-ITDmut AML across four transplant centers in China. Fifty-three patients with triple-mutated AML receiving allo-HSCT in complete remission were enrolled. The 1.5-year probabilities of relapse, leukemia-free survival, and overall survival after allo-HSCT were 11.9%, 80.3%, and 81.8%, respectively. Multivariate analysis revealed that more than one course of induction chemotherapy and allo-HSCT beyond CR1 were associated with poor survival. To our knowledge, this work is the largest study to explore the up-to-date undefined role of allo-HSCT in patients with triple-mutated AML. Our real-world data suggest that allo-HSCT could overcome the poor prognosis of DNMT3AmutNPM1mutFLT3-ITDmut in AML.

Survival impact of hypoxia-inducible factor-1 alpha (HIF-1α) in Nucleophosmin1 mutated acute myeloid leukemia.

Nucleophosmin1 (NPM1) mutated acute myeloid leukemia (AML) without FLT3-ITD mutation is classified as a favorable risk AML which responds well to cytarabine therapy. Hypoxia-inducible factor-1 alpha (HIF-1α) promotes leukemic cell survival and maintains leukemic stem cell quiescence possibly contributing to cytarabine resistance. This study evaluated HIF-1α expression using immunohistochemistry in bone marrow of 29 newly diagnosed NPM1+FLT3-ITD- normal karyotype AML patients and analyzed its correlation with survival. All patients achieved complete remission after standard induction chemotherapy and proceeded to cytarabine consolidations. Positive HIF-1α staining with golgi body pattern and strong cytoplasmic HIF-1α expression was identified in 34.5% and 58.6% of patients, respectively. The expression of golgi body or strong cytoplasmic HIF-1α expression was related to increased relapse (p = 0.048) with significantly inferior relapse-free survival (RFS, p = 0.042). Using multivariate analysis, extramedullary disease at diagnosis was revealed as an independent prognostic factor for adverse RFS (hazard ratio [HR] 3.82; 95% confidence interval [CI] 1.26-11.55, p = 0.018), while golgi body or strong cytoplasmic HIF-1α expression showed a trend toward poor RFS (HR 3.56; 95% CI 1.00-12.69, p = 0.050). In summary, high HIF-1α expression is potentially a baseline prognostic biomarker for poor RFS and cytarabine resistance in NPM1+FLT3-ITD- AML. Further studies with the large number of patients are warranted.

The Clinical Impact of NPM1 Mutations and the Effect of Concurrent Mutations in Acute Myeloid Leukemia: Unraveling the Prognostic Significance.

Nucleophosmin (NPM1) gene mutations occur in approximately 30%-35% of individuals with an initial diagnosis of acute myeloid leukemia (AML). Mutations in this gene have been reported in 50%-60% of AML patients with a normal karyotype. These mutations help to distinguish clinicopathological and molecular features, setting them apart as a unique subset within the heterogeneous landscape of AML. In the present study, we investigated the frequency and clinical impact of NPM1 mut in 100 newly diagnosed adult Syrian patients with AML-normal karyotype (NK) using direct sequencing. We analyzed 100 AML-NK patients using direct sequencing to assess the prevalence and clinical impact of NPM1 mutations, as well as the co-occurrence of FLT3-ITD and DNMT3A mutations. Our results revealed that the prevalence of NPM1 mut was 22% among the patients; 86.4% of these mutations were type A (NM_002520.5:c.860-863dupTCTG), while 13.6% were de novo mutations (c.863_864insCCTG, p.Trp288CysfsTer12), (c.861_862dup, p.Trp288SerfsTer13), and (c.863_864insCCGG, p.Trp288CysfsTer12). Among our patients, 22% exhibited NPM1 mut, with 7% also harboring FLT3-ITD mut and 2% having DNMT3A mut. The presence of NPM1 mut was correlated with a statistically significant increase in bone marrow blast percentage (p = 0.017). Notably, patients with NPM1 mut displayed significantly higher mortality rates, with 72.7% succumbing to the disease compared to 29.5% of patients without NPM1 mut (p < 0.001). Furthermore, our results showed that when the overall survival (OS) time exceeded 8.35 months, the likelihood of NPM1 wild-type status was greater. The evaluation of NPM1 mut and co-mutation has consistently demonstrated remarkable prognostic significance in AML, suggesting the potential for improved response rates, extended disease-free periods, and OS. Our findings provide valuable insights for understanding molecular leukemogenesis in AML-NK patients and will aid in clinical diagnosis, prognostic implications, and the development of targeted therapy strategies for Syrian AML patients.

Salvage Therapy with Second-Generation Inhibitors for FLT3 Mutated Acute Myeloid Leukemia: A Real-World Study by the CETLAM and PETHEMA Groups.

Patients with relapsed/refractory (R/R) AML with FLT3 mutation (FLT3mut) have a dismal prognosis. FLT3mut offers a target for therapy in these patients. Gilteritinib (gilter) and quizartinib (quizar) have demonstrated efficacy as single agents in two phase 3 clinical trials. We retrospectively analyzed the characteristics, treatments, and outcomes of 50 patients with R/R FLT3mut AML who received gilter or quizar as monotherapy in 27 Spanish centers before their commercial availability. Forty-four patients were treated with gilter and six with quizar. The median age was 62.5 years, and 52% were women. Most patients presented with FLT3-ITD mutations (80%); 46% had refractory disease and 54% had relapsed disease at treatment initiation. First-line treatment was chemotherapy in 80% of patients, with 40% of these also receiving midostaurin. Twenty-five patients (50%) had previously received FLT3 inhibitor, and twenty-eight (56%) had received more than one line treatment before starting gilter/quizar. The rates of complete remission (CR), CR without hematological recovery (CRi), and partial remission were 22%, 18%, and 16%, respectively. The median overall survival (OS) and disease-free survival were 4.74 months and 2.99 months, respectively. We observed a significant improvement in OS in patients who had received only one prior line of therapy compared to those who had received two or more therapies (10.77 months vs. 4.24 months, p = 0.016). Multivariate analysis identified failure to achieve CR/CRi, receiving more than one prior line of therapy, age, and white blood cells count as independent prognostic factors for OS. The most common toxicities were febrile neutropenia, liver function abnormalities, and QT interval prolongation. Gilter/quizar monotherapy are effective and tolerable options for patients with R/R FLT3mut AML in a real-world setting. Response and toxicity rates are similar to those reported in the phase 3 trials, despite the more heterogeneous nature of the study population.

Evolving racial/ethnic disparities in AML survival in the novel therapy era

AbstractLittle is known about the impact of recent advances in acute myeloid leukemia (AML) treatment on racial/ethnic disparities in survival outcomes. We performed a retrospective cohort study of patients with newly diagnosed AML using data from a nationwide electronic health record–derived deidentified database. Patients were categorized based on their diagnosis date relative to venetoclax approval, as pre–novel therapy era (Pre era; 2014-2018; n = 2998) or post–novel therapy era (Post era; 2019-2022; n = 2098). Patients in the Post era were older and had more comorbidities than Pre era. Non-Hispanic Black (NHB) and Hispanic patients were younger and more likely to have lower socioeconomic status than non-Hispanic White (NHW) patients, with no differences in the distributions of key disease features. After accounting for age and comorbidity, overall survival (OS) was higher in patients in Post era than Pre era (adjusted hazard ratio [aHR], 0.90; 95% confidence interval [CI], 0.83-0.96; predicted 2-year survival, 39.4% vs 35.3%). In Pre era, NHB had a 22% higher hazard of death than NHW (aHR, 1.22; 95% CI, 1.04-1.43; predicted 2-year survival, 28.6% vs 35.8%), whereas worse OS was not observed for NHB in Post era (aHR, 0.86; 95% CI, 0.69-1.08; predicted 2-year survival, 45.3% vs 39.9%). Utilization of novel therapeutics in frontline therapy did not differ by race/ethnicity in either era. Among patients receiving venetoclax-based induction, particularly those without TP53, RAS, or FLT3-ITD mutations, results suggested higher OS for NHB than NHW patients (aHR, 0.67; 95% CI, 0.45-1.01; predicted 2-year survival, 45.5% vs 31.1%). Additional studies are needed to elucidate factors contributing to these observed survival differences and to inform strategies to optimize outcomes for all patients with AML.

OXPHOS mediators in acute myeloid leukemia patients: Prognostic biomarkers and therapeutic targets for personalized medicine

BackgroundDespite significant advances in comprehending its tumorigenic role, the prognostic and therapeutic potential of targeting oxidative phosphorylation (OXPHOS) in acute myeloid leukemia (AML) remain obscure.MethodsThe prognostic value of ~ 200 mitochondrial/OXPHOS genes as candidate biomarkers was examined in AML patients over ~ 10 years follow-up using Kaplan–Meier and Cox regression analyses. Furthermore, the transcript levels of the assessed markers were inspected in healthy bone marrow tissues and the dependencies of AML cells on the assessed genes were examined.ResultsElevated levels of NADH:ubiquinone oxidoreductase subunit A6 (NDUFA6), succinate dehydrogenase complex flavoprotein subunit A (SDHA), solute carrier family 25 member 12 (SLC25A12), electron transfer flavoprotein subunit beta (ETFB), carnitine palmitoyltransferase 1A (CPT1A) and glutathione peroxidase 4 (GPX4) were associated with poor overall survival of AML patients. SLC25A12, ETFB and CPT1A were overexpressed in AML compared to healthy tissues. Cytochrome B5 type A (CYB5A)high, SLC25A12high and GPX4high AML patients displayed higher levels of circulating and engrafted blasts compared to low-expressing cohorts. NPM1 and SRSF2 mutations were frequent in SDHAlow and CPT1Alow AML patients respectively. FLT3-ITD, NPM1 and IDH1 mutations were prevalent in CPT1Ahigh AML patients. FLT3-ITD AMLs were more dependent on OXPHOS.ConclusionsThis study identifies NDUFA6 and SDHA as novel companion prognostic biomarkers which might present a rational strategy for personalized therapy of AML patients.Graphical

Outcomes of Children and Adolescents with Acute Myeloid Leukemia and FLT3-ITD Treated with Low- or Standard-Dose Chemotherapy Plus Sorafenib on the Cals III-AML18 Trial (ChiCTR1800015883)

Background: FLT3 -ITD mutations are linked to a poor prognosis in pediatric acute myeloid leukemia (AML). Combining targeted therapies, such as sorafenib, with chemotherapy may enhance outcomes for these patients. Low-dose chemotherapy (LDC) has demonstrated safety and effectiveness in some cases. We aimed to investigate whether combining LDC or standard-dose chemotherapy (SDC) with sorafenib can improve the prognosis of patients with FLT3-ITD-positive AML. Methods: From June 2018 to June 2022, this multicenter clinical trial enrolled 497 children with newly diagnosed acute myeloid leukemia (AML), who were randomly assigned to receive either low-dose chemotherapy (LDC) or standard-dose chemotherapy (SDC). Among these, 60 patients were positive for FLT3-ITD mutations. Sorafenib was administered based on recommendations of physicians at a dosage of 200 mg/m²/day. We compared clinical characteristics and outcomes between patients receiving sorafenib (n=40) and those not receiving sorafenib (n=20), focusing on rates of complete morphologic remission with or without platelet recovery (CR/CRi), overall survival (OS), and event-free survival (EFS). Results: There were no significant differences in clinical and biological characteristics between the sorafenib and non-sorafenib groups. Of the 60 patients with AML harboring FLT3-ITD mutations, 33 received sorafenib starting from Induction I. After Induction I, complete morphologic remission with or without platelet recovery (CR/CRi) was achieved in 48.5% of patients in the sorafenib group and 59.3% in the non-sorafenib group (P = .405). However, the CR rate was significantly higher in the for the patients in the LDC group compared to the ones treated with SDC (73.3% vs. 33.3%, P = .002), regardless of sorafenib administration. The median time to neutrophil count recovery was 24 days for patients receiving sorafenib compared to 19.5 days for those not receiving sorafenib after Induction I (P = .0482). The median time to platelet count recovery was 16 days for the sorafenib group and 17.5 days for the non-sorafenib group (P = .0938). Sorafenib did not improve OS or EFS). Patients in the sorafenib group had a 3-year OS of 84.5% ± 5.8% compared to 69.9% ± 11.6% in the non-sorafenib group (P = .336) and a 3-year EFS of 53.1% ± 8.2% versus 54.0% ± 11.4% (P = .862). Eighty-five percent of patients underwent allogeneic hematopoietic stem cell transplantation (HSCT) during their first complete remission (CR1), which significantly improved OS and EFS in patients with FLT3-ITD AML (P = .000). The combination of sorafenib with LDC significantly improved 3-year EFS compared to SDC (66.9% vs. 40.0%, P = .030). In multivariate analysis, sorafenib was not associated with improved outcomes in FLT3-ITD-positive pediatric AML. Conclusion: Patients with FLT3-ITD-positive AML treated with LDC with and without sorafenib achieved favorable remission. Allogeneic hematopoietic stem cell transplantation (HSCT) during first complete remission (CR1) significantly improved overall survival (OS) and event-free survival (EFS). However, sorafenib did not show a significant improvement in prognosis for pediatric patients with FLT3-ITD positive AML in this study, indicating that further randomized controlled trials may be needed to confirm its efficacy.

PRDM16 Induces Methylation of FLT3 to Promote FLT3-ITD Signaling and Leukemia Progression.

Internal tandem duplication (ITD) in the FMS-like receptor tyrosine kinase-3 (FLT3) is one of the most frequent mutations in acute myeloid leukemia (AML) and is associated with poor prognosis. FLT3-ITD mutations result in endoplasmic reticulum (ER) retention and constitutive autophosphorylation of FLT3. The PR/SET domain 16 (PRDM16) is highly expressed in FLT3-ITD+ AML patients, suggesting it might play a role in leukemogenesis. Here, we revealed that genetic and pharmacological suppression of PRDM16 greatly slowed the progression of FLT3-ITD-driven leukemia, sensitized leukemic cells to tyrosine kinase inhibitors (TKIs), and extended the survival of leukemic mice. PRDM16 enhanced activation of oncogenic FLT3-ITD and ligand-dependent activation of wild-type FLT3 in leukemic cells. Mechanistically, PRDM16 mediated monomethylation of FLT3-ITD at lysine 614 and promoted its ER localization, resulting in enhanced FLT3 signaling in leukemia cells. Moreover, pharmacological suppression of FLT3-ITD methylation in combination with TKIs increased the elimination of FLT3-ITD+ AML cells. Altogether, these results suggest that PRDM16 boosts oncogenic FLT3 signaling in leukemic cells by prompting FLT3-ITD methylation. Therefore, PRDM16 may serve as a therapeutic target for AML.

Prognostic impact of 'multi-hit' versus 'single-hit' TP53 alteration in patients with acute myeloid leukemia: results from the Consortium on Myeloid Malignancies and Neoplastic Diseases.

While there is clear evidence to suggest poorer outcome associated with multi-hit (MH) TP53 mutation (TP53MT) compared to a single-hit (SH) mutation in lower-risk myelodysplastic syndrome (MDS), data are conflicting in both higher-risk MDS and acute myeloid leukemia (AML). We conducted an in-depth analysis utilizing data from ten US academic institutions to study differences in molecular characteristics and outcomes of SH (N=139) versus MH (N=243) TP53MT AML. Complex cytogenetics were more common in MH than in SH TP53MT AML (P<0.001); whereas ASXL1 (P<0.001), RAS (P<0.001), splicing factor (P=0.003), IDH1/2 (P=0.001), FLT3 ITD (P<0.001) and NPM1 (P=0.005) mutations clustered significantly with SH TP53MT AML. Survival after excluding patients who received best supportive care alone was dismal but not significantly different between patients with SH or MH disease (event-free survival: 3.0 vs. 2.20 months, respectively, P=0.22; overall survival: 8.50 vs. 7.53 months, respectively, P=0.13). In multivariable analysis, IDH1 mutation and allogeneic hematopoietic stem cell transplantation as a time-dependent covariate were associated with superior event-free survival (hazard ratio [HR]=0.44, 95% confidence interval [95% CI]: 0.19-1.01, P=0.05 and HR=0.34, 95% CI: 0.18-0.62, P<0.001) and overall survival (HR=0.24, 95% CI: 0.08-0.71, P=0.01 and HR=0.28, 95% CI: 0.16-0.47, P<0.001). Complex cytogenetics (HR=1.56, 95% CI: 1.01-2.40, P=0.04) retained an unfavorable significance for overall survival. Our analysis suggests that MH TP53MT is less relevant in independently predicting outcomes in patients with AML than in those with MDS.

The prognostic significance of genetics in acute myeloid leukemia under venetoclax-based treatment.

Acute myeloid leukemia (AML) is the most prevalent hematologic malignancy in adults. In 2022, the European LeukemiaNet (ELN) has updated its prognostic system that incorporates cytogenetics and molecular genetics based on data from patients undergoing intensive chemotherapy (IC). Recently, a risk stratification framework has been established for hypomethylating agents (HMA)-based low-intensity treatment (LIT) to fill the gaps in stratification for this treatment modality, but this needs further refinement. Venetoclax (VEN), a BH3 mimetic, targets BCL-2 to modulate apoptosis and metabolism in AML cells. Its combination with HMA or low-dose cytarabine (LDAC) has been shown to enhance the response rates and prolong the survival outcomes of older or unfit patients with AML. In this review, we delved into the prognostic significance of FLT3-ITD and IDH mutations when used in combination with VEN and HMA, as well as in conjunction with their specific inhibitors. We also explored the role of VEN in NPM1-mutated AML and its efficacy in splicing factor mutations AML. Additionally, we examined the response rates and survival outcomes of CBF-AML when treated with a VEN-based regimen. Moving forward, it is imperative that risk stratification for LIT becomes more nuanced to better align with the requirements of personalized diagnosis and treatment strategies.

Quizartinib Therapy for FLT3-positive Acute Myeloid Leukaemia.

Madam, Globally, acute myeloid leukaemia (AML) is a common concern among leukaemia patients. It is the most common form of leukaemia in adults. Various genetic mutations are associated with AML. Around 30% of patients carry mutations in the FLT3 receptor, with LT3-ITD being the most common and associated with a poor prognosis1. Current treatment for this type of AML in Pakistan includes induction chemotherapy with Daunorubicin and Idarubicin, followed by allogeneic stem cell transplant or cytarabine.2 Quizartinib is a new oral agent that selectively targets the FLT3-ITD mutation and has shown promising results in a newly conducted trial, the QuANTUM-First trial. The trial shows that adding Quizartinib to standard chemotherapy with or without allogeneic stem cell transplant, followed by monotherapy with the drug for up to 3 years, resulted in improved overall survival in adults aged 18–75 years with FLT3-ITD-positive newly diagnosed AML.3 This information is crucial for physicians treating AML in Pakistan, as targeted therapeutic agents like Quizartinib must be studied and developed here. Trials should be conducted to reveal the efficacy and safety of these agents specific to the Pakistani population, as these could drastically improve the survival rate and overall prognosis of AML patients.