A Phase II Study of Elacytarabine/Idarubicin As Second Course Remission-Induction in Patients with Acute Myeloid Leukemia Who Failed Cytarabine/Anthracycline, and Evaluation of the Impact of the Nucleoside Transporter hENT1 on Response

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1533-1533
Author(s):  
David A. Rizzieri ◽  
Norbert Vey ◽  
Richard F. Schlenk ◽  
Xavier Thomas ◽  
Françoise Huguet ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Confidence Interval ◽  
Myeloid Leukemia ◽  
Fatty Acid Derivative ◽  
Expression Level ◽  
Remission Induction ◽  
Clinical Activity ◽  
Nucleoside Transporter ◽  
The Impact ◽  
Acute Myeloid

Abstract Abstract 1533 Background: Elacytarabine is a fatty acid derivative (elaidic acid ester) of cytarabine. The mechanism of action is similar to cytarabine, but unlike cytarabine, cellular uptake and activity of elacytarabine are independent of nucleoside transporters. Resistance to cytarabine has been associated with decreased expression of the human equilibrative nucleoside transporter 1 (hENT1) (Hubeek et al., 2005). An agent such as elacytarabine, active in low hENT1 expressing, cytarabine resistant acute myeloid leukemia (AML), could therefore improve clinical outcome in patients. Aims: To determine the efficacy and safety of elacytarabine given in combination with idarubicin to patients who have failed the first ”standard” induction course with a cytarabine based regimen, as well as to explore the relationship between the hENT1 status in AML cells and response. Methods: Study therapy consisted of one course elacytarabine 1000 mg/m2/d CIV on d1-5 administered in combination with idarubicin 12 mg/m2/d IV d1-3 in adult patients with AML who after a first cytarabine based induction course have not attained blast clearance (bone marrow (BM) >5 % blasts, circulating blasts, or chloroma etc). Assessment of response was at least 12d after induction start. Responding patients could receive the same course or elacytarabine 2000 mg/m2/d CIV on d1-5 d and then consolidation therapy with two courses of either elacytarabine monotherapy or combination with idarubicin as described above or could proceed to allogeneic SCT at any time point. The hENT1 expression level of BM blasts was analyzed by immunocytochemistry at time of initial AML diagnosis (pre-cytarabine course) and/or before elacytarabine treatment. The planned sample size is 50 evaluable patients, and with a target of 40% CR/CRi rate, the lower limit of the 90% confidence interval for the CR/CRi rate will be greater than 22% with at least 80% probability. The CR/CRi rate will be estimated and its corresponding two-sided 90% confidence interval will be provided. The significance of the association between the hENT1 expression level and response status will be assessed through a Chi-square test of hENT1 expression level (high, low) versus CR/CRi (yes, no). Results: In the ongoing study, 26 patients [16 male, 10 female, median age 61 years (range 18–71), ECOG PS 0–2] have been treated with elacytarabine and idarubicin. 23 patients have currently been response evaluated, and 11 attained a CR/CRi and 3 a PR (post one elacytarabine course). The most frequently reported related non-hematologic adverse events (AEs) CTCAE grade ≥ 3 were febrile neutropenia, infections/sepsis and increased liver function tests. 30 patients have been scored for hENT1 expression level at time of diagnosis. Preliminary results indicate that approximately 50 % of the patients hENT1 expression is low (defined as less than 10% of blasts stained). As to response, only approximately 1/3 of patients with low hENT1 blasts respond to cytarabine while for the high hENT1 2/3 respond. Three deaths occurred within 30 days after start of treatment and were all due to sepsis. All 3 patients had secondary leukemia. Summary/Conclusion: Elacytarabine administered at 1000 mg/m2/d CIV d1-5 in combination with idarubicin 12mg/m2/d IV d1-3 showed promising clinical activity with a CR/CRi rate of approximately 45 %. The adverse event profile, is as expected for cytarabine combination therapy. Preliminary data indicate that the assessment of hENT1 transporter expression in blasts could be used to select patients less likely to benefit from cytarabine and for whom elacytarabine could be an effective therapy. Disclosures: Gianelli-Borradori: Clavis Pharma: Employment. Flem Jacobsen:Clavis Pharma: Employment. Krug:MedA Pharma: Honoraria; Novartis: Honoraria; Alexion: Honoraria; Boehringer Ingelheim: Research Funding; Sunesis: Honoraria.

scholarly journals Ecological principle meets cancer treatment: treating children with acute myeloid leukemia with low-dose chemotherapy

2019 ◽  
Vol 6 (3) ◽  
pp. 469-479 ◽  
Author(s):  
Yixin Hu ◽  
Aili Chen ◽  
Xinchang Zheng ◽  
Jun Lu ◽  
Hailong He ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Low Dose ◽  
Randomized Study ◽  
Remission Induction ◽  
Molecular Response ◽  
Standard Chemotherapy ◽  
Low Dose Chemotherapy ◽  
The Impact ◽  
Acute Myeloid

Abstract Standard chemotherapy regimens for remission induction of pediatric acute myeloid leukemia (AML) are associated with significant morbidity and mortality. We performed a cohort study to determine the impact of reducing the intensity of remission induction chemotherapy on the outcomes of selected children with AML treated with a low-dose induction regimen plus granulocyte colony stimulating factor (G-CSF) (low-dose chemotherapy (LDC)/G-CSF). Complete response (CR) after two induction courses was attained in 87.0% (40/46) of patients receiving LDC/G-CSF. Post-remission therapy was offered to all patients, and included standard consolidation and/or stem cell transplantation. During the study period, an additional 94 consecutive children with AML treated with standard chemotherapy (SDC) for induction (80/94 (85.1%) of the patients attained CR after induction II, P = 0.953) and post-remission. In this non-randomized study, there were no significant differences in 4-year event-free (67.4 vs. 70.7%; P = 0.99) and overall (70.3 vs. 74.6%, P = 0.69) survival in the LDC/G-CSF and SDC cohorts, respectively. After the first course of induction, recovery of white blood cell (WBC) and platelet counts were significantly faster in patients receiving LDC/G-CSF than in those receiving SDC (11.5 vs. 18.5 d for WBCs (P < 0.001); 15.5 vs. 22.0 d for platelets (P < 0.001)). To examine the quality of molecular response, targeted deep sequencing was performed. Of 137 mutations detected at diagnosis in 20 children who attained hematological CR after two courses of LDC/G-CSF (n = 9) or SDC (n = 11), all of the mutations were below the reference value (variant allelic frequency <2.5%) after two courses, irrespective of the treatment group. In conclusion, children with AML receiving LDC/G-CSF appear to have similar outcomes and mutation clearance levels, but significantly lower toxicity than those receiving SDC. Thus, LDC/G-CSF should be further evaluated as an effective alternative to remission induction in pediatric AML.

scholarly journals New directions for emerging therapies in acute myeloid leukemia: the next chapter

2020 ◽  
Vol 10 (10) ◽  
Author(s):  
Naval Daver ◽  
Andrew H. Wei ◽  
Daniel A. Pollyea ◽  
Amir T. Fathi ◽  
Paresh Vyas ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Early Stage ◽  
Myeloid Cell ◽  
B Cell Lymphoma ◽  
Remission Induction ◽  
Clinical Activity ◽  
Significant Shift ◽  
Hypomethylating Agent ◽  
Acute Myeloid

Abstract Conventional therapy for acute myeloid leukemia is composed of remission induction with cytarabine- and anthracycline-containing regimens, followed by consolidation therapy, including allogeneic stem cell transplantation, to prolong remission. In recent years, there has been a significant shift toward the use of novel and effective, target-directed therapies, including inhibitors of mutant FMS-like tyrosine kinase 3 (FLT3) and isocitrate dehydrogenase (IDH), the B-cell lymphoma 2 inhibitor venetoclax, and the hedgehog pathway inhibitor glasdegib. In older patients the combination of a hypomethylating agent or low-dose cytarabine, venetoclax achieved composite response rates that approximate those seen with standard induction regimens in similar populations, but with potentially less toxicity and early mortality. Preclinical data suggest synergy between venetoclax and FLT3- and IDH-targeted therapies, and doublets of venetoclax with inhibitors targeting these mutations have shown promising clinical activity in early stage trials. Triplet regimens involving the hypomethylating agent and venetoclax with FLT3 or IDH1/2 inhibitor, the TP53-modulating agent APR-246 and magrolimab, myeloid cell leukemia-1 inhibitors, or immune therapies such as CD123 antibody-drug conjugates and programmed cell death protein 1 inhibitors are currently being evaluated. It is hoped that such triplets, when applied in appropriate patient subsets, will further enhance remission rates, and more importantly remission durations and survival.

scholarly journals Importance of Altered Gene Expression of Metalloproteinases 2, 9, and 16 in Acute Myeloid Leukemia: Preliminary Study

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Jacek Pietrzak ◽  
Marek Mirowski ◽  
Rafał Świechowski ◽  
Damian Wodziński ◽  
Agnieszka Wosiak ◽  
...  
Keyword(s):  
Gene Expression ◽  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Proteolytic Enzymes ◽  
Regulation Of Gene Expression ◽  
Expression Level ◽  
Altered Expression ◽  
Cytogenetic Changes ◽  
The Impact ◽  
Acute Myeloid

Acute myeloid leukemia is a group of hematological neoplasms characterized by a heterogeneous course and high mortality. The important factor in the neoplastic process is metalloproteinases, proteolytic enzymes capable of degrading various components of the extracellular matrix, which take an active part in modifying the functioning of the cell, including transformation to cancer cell. They interact with numerous signaling pathways responsible for the process of cell growth, proliferation, or apoptosis. In the present study, changes in the expression of MMP2, MMP9, and MMP16 genes between patients with AML and people without cancer were examined. The impact of cytogenetic changes in neoplastic cells on the expression level of MMP2, MMP9, and MMP16 was also assessed, as well as the impact of the altered expression on the effectiveness of the first cycle of remission-inducing therapy. To evaluate the expression of all studied genes MMP2, MMP9, and MMP16, SYBR Green-based real-time PCR method was used; the reference gene was GAPDH. For two investigated genes MMP2 and MMP16, the lower expression level was observed in patients with AML when compared to healthy people. The MMP9 gene expression level did not differ between patients with AML and healthy individuals which may indicate a different regulation of gene expression in acute myeloid leukemia. However, no correlation was observed between the genes’ expression of all tested metalloproteinases and the result of cytoreductive treatment or the presence of cytogenetic changes. The obtained results show that the expression of MMP2 and MMP16 genes is reduced while the expression of MMP9 is unchanged in patients with acute myeloid leukemia. This may indicate a different regulation of the expression of these genes, and possible disruptions in gene transcription or posttranscriptional mechanisms in the MMP2 and MMP16 genes, however, do not affect the level of MMP9 expression. Obtained results in AML patients are in contrary to various types of solid tumors where increased expression is usually observed.

Favorable Impact of the t(9;11) in Childhood Acute Myeloid Leukemia

2002 ◽  
Vol 20 (9) ◽  
pp. 2302-2309 ◽  
Author(s):  
Jeffrey E. Rubnitz ◽  
Susana C. Raimondi ◽  
Xin Tong ◽  
Deo Kumar Srivastava ◽  
Bassem I. Razzouk ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Relative Risk ◽  
Confidence Interval ◽  
Myeloid Leukemia ◽  
Cox Proportional Hazards Model ◽  
The Other ◽  
Leukemic Cells ◽  
The Impact ◽  
Risk Of Relapse ◽  
Acute Myeloid

PURPOSE: To determine the impact of MLL rearrangements on the outcome of children with acute myeloid leukemia (AML). PATIENTS AND METHODS: We analyzed the clinical and biologic features of 298 infants and children with primary AML treated on four consecutive institutional clinical trials. The Kaplan-Meier method was used in survival analysis and the Cox proportional-hazards model was used to analyze the effect of potential prognostic factors on event-free survival (± 1 SE). RESULTS: Molecular studies of 152 cases detected 42 with MLL rearrangements. The karyotypes of these 42 revealed the t(9;11) (15 cases), abnormalities of chromosomes 10 and 11 (nine cases), the t(11;19) (four cases), other abnormalities of 11q23 (seven cases), and miscellaneous rearrangements (seven cases). Among these 42 patients, the 15 whose leukemic cells carried the t(9;11) had a better outcome (66% ± 15%) than the other 27 (25.9% ± 11.2%; P = .004). Cases with the t(9;11) were also characterized by M5 AML morphology (21 of 23 cases). Of the 63 patients with M5 AML, the 21 whose leukemic cells demonstrated the t(9;11) had a better outcome (71.1% ± 11%) than the other 42 (25.8% ± 7.9%; P = .0004). The only independent factors indicating a favorable prognosis were presenting leukocyte count less than 50 × 109/L (relative risk of relapse, 0.73; 95% confidence interval, 0.55 to 0.97; P = .03) and the t(9;11) (relative risk of relapse, 0.32; 95% confidence interval, 0.16 to 0.64; P = .002). CONCLUSION: We conclude that the t(9;11) is the most favorable genetic factor for patients with AML treated at our institution.

scholarly journals Assessing the Impact of Prophylactic Anidulafungin during Remission Induction of Acute Myeloid Leukemia - a Propensity-Score Matching Analysis

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 1988-1988
Author(s):  
Wellington F Silva ◽  
Fernanda Rodrigues Mendes ◽  
Raphael Bandeira Melo ◽  
Elvira Velloso ◽  
Vanderson Rocha ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Propensity Score ◽  
Genetic Risk ◽  
Myeloid Leukemia ◽  
Complete Response ◽  
Remission Induction ◽  
Fusarium Sp ◽  
The Impact ◽  
Acute Myeloid

Abstract Introduction: Invasive fungal disease (IFD) accounts for substantial morbidity during the treatment of acute myeloid leukemia (AML) in adults. Antifungal prophylaxis (AP) is needed during intensive chemotherapy, and posaconazole has recently emerged as a drug of choice for this purpose. In our setting, alternative strategies such as no upfront prophylaxis, fluconazole, or echinocandins have been used during the remission induction, as posaconazole is not available. While few reports have pointed to micafungin as an option for this aim, studies addressing the use of anidulafungin in AML are lacking. In this study, we aimed to examine the impact of prophylactic anidulafungin during intensive AML remission induction. Methods: This retrospective cohort encompassing newly diagnosed AML adult patients (pts) treated at Instituto do Cancer do Estado de Sao Paulo, Brazil, between June 2011 and June 2020. We used a slight modification of European LeukemiaNet 2010 classification previously published by our group - Adapted Genetic Risk (AGR) (Silveira et al., 2020). Over these years, local policies regarding AP changed. All patients received the "7+3" regimen and were divided into three groups: pts who did not receive any AP and pts who received fluconazole (15-400 mg/day) or anidulafungin (100 mg/day) as AP. Local recommendations for IFD treatment were followed, and they also changed over time. The primary endpoint was IFD rate during the first 60 days from the beginning of chemotherapy, following the recommendation of EORTC/MSG. Multivariable analysis (MVA) was performed by logistic regression. Aiming to equalize subgroups for IFD risk factors, a propensity-score matching was performed using the nearest neighbor method. Results: Overall, 204 pts were included, with a median age of 54 years (range,17-74). The main baseline features of this cohort are summarized in Table 1. Regarding AP, 108 pts received anidulafungin, 82 pts did not receive AP, and 14 pts received fluconazole. The incidence of IFI was 26.6% (95% CI 20.8-33.3), classified as possible, probable, and proven in 65.5%, 1.8%, and 32.7%, respectively. Regarding the fungus specimen, Aspergillus sp. responded for most cases (60%), followed by Fusarium sp. (23%), Candida sp. (11%), and Zygomycetes (4%). Complete response was documented at the end of induction in 49%, with the remaining patients being either refractory (27%) or not available (24%). The 60-day mortality was 25.8%. MVA showed that lower neutrophil counts at the AML diagnosis are associated with IFD during induction (OR=2.8, 95% CI 1.3-6.2), whereas age, genetic classification, and lymphocyte counts were not. Comparing the three abovementioned groups (AP: none, anidulafungin, or fluconazole), significant differences could be seen in AGR and anthracycline doses (Table 2). To analyze the impact of anidulafungin in comparison with 'no AP', a post-matched cohort with 164 subjects was created, matching for neutrophil and lymphocyte counts and AGR. The use of anidulafungin was not significantly related to less IFD during induction (OR=0.7, 95% CI 0.3-1.6), while neutrophil counts remained significant. Few subjects received fluconazole as AP, and it also was not related to less IFD (p=0.35). At the end of induction, complete response status did not relate to IFD during this period (p=1). Treatment for IFD with amphotericin B and voriconazole was given for 60.2% and 13.1% during induction, respectively. Patients under prophylactic anidulafungin received less amphotericin B (p&lt;0.001) but not voriconazole (p=0.49). Fusarium sp. cases that occurred during induction (n=12) received mostly prophylactic fluconazole (42%), which was statistically relevant in comparison to other AP (p&lt;0.001). Among these 12 cases, no favorable genetic risk was found. The occurrence of IFD during induction did not correlate with early mortality (HR=0.97, 95% CI 0.5-1.8) in our cohort. Conclusion: To our knowledge, this is the first study addressing the role of anidulafungin during AML induction. Here, the use of AP did not decrease IFD incidence within this phase. Our results point to the fact that the fungistatic activity of echinocandins in molds might be suboptimal for immunocompromised pts. Furthermore, these results strengthen the role of posaconazole in this setting, especially for baseline neutropenic patients or higher risk subsets, such as primary refractory cases. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

The favorable impact of CEBPA mutations in patients with acute myeloid leukemia is only observed in the absence of associated cytogenetic abnormalities and FLT3 internal duplication

Blood ◽  
2009 ◽  
Vol 113 (21) ◽  
pp. 5090-5093 ◽  
Author(s):  
Aline Renneville ◽  
Nicolas Boissel ◽  
Nathalie Gachard ◽  
Dina Naguib ◽  
Christian Bastard ◽  
...  
Keyword(s):  
Overall Survival ◽  
Acute Myeloid Leukemia ◽  
Confidence Interval ◽  
Myeloid Leukemia ◽  
Normal Karyotype ◽  
Favorable Outcome ◽  
Abnormal Karyotype ◽  
Cytogenetic Abnormalities ◽  
The Impact ◽  
Acute Myeloid

AbstractMutations of the CCAAT/enhancer binding protein alpha (CEBPA) gene have been associated with a favorable outcome in patients with acute myeloid leukemia (AML), but mainly in those with a normal karyotype. Here, we analyzed the impact of associated cytogenetic abnormalities or bad-prognosis fms-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD) in 53 patients with CEBPA+ de novo AML treated in the Acute Leukemia French Association trials. We found that only those with a normal karyotype and no FLT3-ITD displayed the expected favorable outcome. In this context, relapse-free, disease-free, and overall survival were significantly longer than in corresponding patients without the CEBPA mutation (P = .035, .016, and .047, respectively). This was not observed in the context of an abnormal karyotype or associated FLT3-ITD. Furthermore, after adjustment on age, trial, and mutation type, these features were independently predictive of shorter overall survival in the subset of patients with CEBPA+ AML (multivariate hazard ratio = 2.7; 95% confidence interval, 1.08-6.7; and 2.9; 95% confidence interval, 1.01-8.2; with P = .034 and .05, for abnormal karyotype and FLT3-ITD, respectively).

scholarly journals Age and remission induction therapy for acute myeloid leukemia: An analysis of data from the Korean acute myeloid leukemia registry

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0251011
Author(s):  
Kwai Han Yoo ◽  
Hyeoung-Joon Kim ◽  
Yoo Hong Min ◽  
Dae-Sik Hong ◽  
Won Sik Lee ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Induction Therapy ◽  
Myeloid Leukemia ◽  
Therapeutic Strategy ◽  
Median Overall Survival ◽  
Complete Response ◽  
Remission Induction ◽  
The Impact ◽  
Acute Myeloid

Objective The clinical characteristics and therapeutic strategy in acute myeloid leukemia (AML) are influenced by patients’ age. We evaluated the impact of age on remission induction therapy for AML. Methods We retrospectively analyzed 3,011 adult AML patients identified from a nationwide database between January 2007 and December 2011. Results Three hundred twenty-nine (10.9%) acute promyelocytic leukemia (APL) and 2,682 (89.1%) non-APL patients were analyzed. The median age was 51 years and 55% of patients were male. Six hundred twenty-three patients (21%) were at favorable risk, 1522 (51%) were at intermediate risk, and 743 (25%) were at poor risk. As the age increased, the proportion of those at favorable risk and who received induction chemotherapy decreased. After induction therapy, complete response (CR) was achieved in 81.5% (243/298) of APL and 62.4% (1,409/2,258) of non-APL patients; these rates decreased as the age increased, with an obvious decrement in those older than 60 years. The median overall survival of non-APL patients was 18.7 months, while that of APL patients was not reached, with a 75% five-year survival rate. Conclusions Age impacts both the biology and clinical outcomes of AML patients. Further studies should confirm the role of induction remission chemotherapy by age group.

AML1/RUNX1 mutations in 470 adult patients with de novo acute myeloid leukemia: prognostic implication and interaction with other gene alterations

Blood ◽  
2009 ◽  
Vol 114 (26) ◽  
pp. 5352-5361 ◽  
Author(s):  
Jih-Luh Tang ◽  
Hsin-An Hou ◽  
Chien-Yuan Chen ◽  
Chieh-Yu Liu ◽  
Wen-Chien Chou ◽  
...  
Keyword(s):  
Overall Survival ◽  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
De Novo ◽  
Remission Rate ◽  
Adult Patients ◽  
Poor Prognostic Factor ◽  
The Impact ◽  
Runx1 Mutation ◽  
Acute Myeloid

AbstractSomatic mutation of the AML1/RUNX1(RUNX1) gene is seen in acute myeloid leukemia (AML) M0 subtype and in AML transformed from myelodysplastic syndrome, but the impact of this gene mutation on survival in AML patients remains unclear. In this study, we sought to determine the clinical implications of RUNX1 mutations in 470 adult patients with de novo non-M3 AML. Sixty-three distinct RUNX1 mutations were identified in 62 persons (13.2%); 32 were in N-terminal and 31, C-terminal. The RUNX1 mutation was closely associated with male sex, older age, lower lactic dehydrogenase value, French-American-British M0/M1 subtypes, and expression of HLA-DR and CD34, but inversely correlated with CD33, CD15, CD19, and CD56 expression. Furthermore, the mutation was positively associated with MLL/PTD but negatively associated with CEBPA and NPM1 mutations. AML patients with RUNX1 mutations had a significantly lower complete remission rate and shorter disease-free and overall survival than those without the mutation. Multivariate analysis demonstrated that RUNX1 mutation was an independent poor prognostic factor for overall survival. Sequential analysis in 133 patients revealed that none acquired novel RUNX1 mutations during clinical courses. Our findings provide evidence that RUNX1 mutations are associated with distinct biologic and clinical characteristics and poor prognosis in patients with de novo AML.

scholarly journals Actin cytoskeleton deregulation confers midostaurin resistance in FLT3-mutant acute myeloid leukemia

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Andoni Garitano-Trojaola ◽  
Ana Sancho ◽  
Ralph Götz ◽  
Patrick Eiring ◽  
Susanne Walz ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Actin Cytoskeleton ◽  
Myeloid Leukemia ◽  
Actin Polymerization ◽  
Cell Stiffness ◽  
Adhesion Forces ◽  
Frequent Mutations ◽  
New Perspective ◽  
The Impact ◽  
Acute Myeloid

AbstractThe presence of FMS-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD) is one of the most frequent mutations in acute myeloid leukemia (AML) and is associated with an unfavorable prognosis. FLT3 inhibitors, such as midostaurin, are used clinically but fail to entirely eradicate FLT3-ITD + AML. This study introduces a new perspective and highlights the impact of RAC1-dependent actin cytoskeleton remodeling on resistance to midostaurin in AML. RAC1 hyperactivation leads resistance via hyperphosphorylation of the positive regulator of actin polymerization N-WASP and antiapoptotic BCL-2. RAC1/N-WASP, through ARP2/3 complex activation, increases the number of actin filaments, cell stiffness and adhesion forces to mesenchymal stromal cells (MSCs) being identified as a biomarker of resistance. Midostaurin resistance can be overcome by a combination of midostaruin, the BCL-2 inhibitor venetoclax and the RAC1 inhibitor Eht1864 in midostaurin-resistant AML cell lines and primary samples, providing the first evidence of a potential new treatment approach to eradicate FLT3-ITD + AML.

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