Adult Acute Myeloid Leukemia Research Articles

Identification of Novel Cell Surface Therapeutic Targets for KMT2A-Rearranged Acute Myeloid Leukemia

INTRODUCTION. Acute myeloid leukemia (AML) is a highly heterogeneous disease that represents 80% of adult leukemias and is characterized by chromosomal rearrangements such as translocations and inversions, as well as genetic mutations. These genomic alterations affect the normal maturation process of myeloid precursor cells and lead to their clonal expansion in the bone marrow and peripheral blood. Genetic aberrations define AML subgroups, which are associated with risk stratification (favorable, intermediate or adverse risk) and prognosis. One AML subgroup, KMT2A-rearranged AML (KMT2Ar), is driven by chromosomal translocations involving the lysine methyltransferase 2A gene (KMT2A) located on chromosome band 11q23.3, leading to gene fusions with over 94 distinct partners. KMT2A rearrangements are present in 5 to 10% of adult AML. Patients with t(9;11)(p21.3;q23.3) translocation generating the MLLT3::KMT2A fusion are classified in the intermediate cytogenetic risk group according to the 2022 ELN genetic risk classification, but KMT2A fusions with other translocation partners are included in the adverse risk group with current therapies. Ongoing clinical trials for KMT2Ar AML focus mainly on chemical inhibitors (DOT1L and Menin inhibitors) that target and disrupt KMT2A fusion protein complexes, with encouraging results. Precision medicine, such as antibody-based immunotherapy, also represents a promising approach for the treatment of KMT2Ar AML, but is currently underexploited due to the limited availability of targetable surface antigens. To overcome this issue, we analyzed the cell surface proteome (surfaceome) of primary human KMT2Ar AML samples to identify novel cell surface antigens with high therapeutic potential. METHODS AND RESULTS. We used a proteomics-based approach to analyze the surfaceome of 100 primary human AML specimens from 13 different AML subgroups, including 13 KMT2Ar AML samples. Briefly, we combined cell surface biotinylation with streptavidin affinity purification to enrich cell extracts with cell surface proteins, which were then analyzed by LC-MS/MS to obtain an overview of primary AML sample surfaceomes. Differential surfaceome analyses were performed to identify surface proteins selectively expressed by KMT2Ar AML specimens, and proteins with low expression in normal hematopoietic cells and normal tissues, as determined by expression analyses using publicly available datasets, were further selected. Using this approach, we identified several potential KMT2Ar AML surface antigens, including CD93, reported to be expressed by KMT2Ar AML stem cells. We then analyzed surface expression of these antigens by flow cytometry using a collection of 112 primary human AML specimens including 10 KMT2Ar AML samples. Results indicate that in the majority of KMT2Ar AML samples analyzed, more than 90% of blasts express selected antigens, suggesting that targeting these antigens with immunotherapeutic approaches could potentially lead to the elimination of most AML cells. Furthermore, flow cytometry data showed specificity of antigen expression for KMT2Ar AML samples, opening new therapeutic opportunities for this AML subgroup. Finally, single cell RNA sequencing of 8 primary KMT2Ar AML specimens was performed to further analyze the expression profile of these antigens in patient samples. AML specimens harboring the MLLT3::KMT2A fusion expressed these antigens in the vast majority of blast cells, confirming the homogeneous expression profile of identified antigens and the high interest to target these antigens for KMT2Ar AML. CONCLUSIONS Using a cell surface proteomics-based approach for the analysis of KMT2Ar AML surfaceome, we identified several antigens for this AML subgroup with high therapeutic potential. These antigens are very specific for KMT2Ar AML and are expressed homogeneously in primary human KMT2Ar AML samples, suggesting that targeting these antigens represents a promising therapeutic strategy for these patients. Several immunotherapeutic approaches to target these antigens are currently being developed and tested by our group, with the hope of identifying novel therapeutic strategies for the treatment of KMT2Ar AML.

Heme Oxygenase-1 Inhibition the Cytotoxicity of NK Cells to AML By Downregulating HLA-C

Backgroud and objective: Acute myeloid leukemia (AML) is a malignant clonal disease of hematopoietic stem cells with abnormal differentiation of myeloid primordial naive cells, which has the highest incidence in adult Acute leukemia with a low cure rate . Clinically, less than one-third of adult AML patients can achieve sustained remission after cytarabine combined with anthracycline chemotherapy, and over 50% relapse after remission. Allogeneic hematopoietic stem cell transplantation (Allo-HSCT) is still the only way to cure leukemia clinically. However, due to age limitation, infection, graft-versus-host disease, and other complications, it is not suitable for all AML patients In recent years, numerous novel drugs have provided more options for the treatment of relapsed and refractory AML while the overall response rate is unsatisfactory and there is no significant advantage in improving overall survival Exploring the mechanism affecting AML relapse and refractory treatment, formulating effective coping strategies are the key to overcome the treatment bottleneck of AML Methods: Bone marrow nucleated cells were obtained from 15 newly diagnosed AML patients, 15 recurrent AML patients and 15 normal controls. The expressions of HO-1 and HLA-C were detected by quantitative reverse transcription PCR (RT-PCR) and Western blot. In vitro cell experiments, we constructed SiHO-1 lentiviral vector to transfect AML cell lines, cocultured NK cells with it, measured the change of CD107a expression on NK cell surface, and silenced HLA-C expression with small interfering RNA. The silenced AML cell lines were co-cultured with NK cells, and CD107a secretion on NK cells was measured by flow cytometry. Results: HO-1 expression in AML patients was higher than that in healthy donors (P<0.05), while HLA-C expression was lower than that in healthy donors (P<0.01). Additionally, the plasma HO-1 levels gradually increased, while the HLA-C levels gradually decreased from healthy donors to patients with relapsed AML. In addition, Pearman correlation analysis indicated that HLA-C expression was significantly correlated with HO-1 expression (r=0.635, P<0.001). In AML cell lines, HO-1 silencing enhanced the cytotoxicity of NK cells to AML cells (P＜0.01), while HO-1 overexpression weakened the cytotoxicity of NK cells to AML cells (P＜0.05). The expression of CD107a in NK cells after HLA-C silencing was lower than the control group in U937 and THP-1 cell line. (P＜0.05). Conclusion: decreased HLA-C expression is associated with increased HO-1 expression during the progression of AML. Besides, the inhibition of HO-1 promotes HLA-C expression, which can therefore promote cytotoxicity of NK cells to AML cells.

Improved Post-Transplant Outcomes in Recent Years for AML Patients with Intermediate Karyotype, FLT3-ITD and Wild Type NPM1: A Report from the EBMT Acute Leukemia Working Party

Rationale: Allogeneic hematopoietic cell transplantation (allo-HCT) is recommended in first complete remission (CR1) in acute myeloid leukemia (AML) patients harboring FLT3 internal tandem duplication (FLT3-ITD). However, historically, long-term survival has been poor due to early relapse, particularly for patients with wild-type NPM1. Recently, FLT3 inhibitors in combination with chemotherapy before allo-HCT, or as post-transplant maintenance, have significantly reduced the risk of relapse and improved survival. Here, we assessed real-world changes over time in transplant characteristics and post-transplant outcomes in young AML patients with FLT3 ITD and either NPM-1 mutated or wild type, using a large dataset from the European Society of Blood and Marrow Transplantation (EBMT) registry. Patients and Methods: We identified 1827 adult AML patients (54% female; median age 49 years, range 18-60) with FLT3 ITD, intermediate karyotype and available NPM1 mutation status, allografted between 2012 and 2021 in CR1 from a matched related (32%), matched unrelated (56%) or haploidentical donor (12%). NPM1 was mutated in 72% of patients. At transplant, 834 patients were measurable residual disease (MRD) positive, 464 MRD negative, and 529 were not evaluated or missing. Comorbidity index (CI) was zero in 59% of patients with available data. Conditioning was myeloablative (MAC) in 64% of patients. In vivo T cell depletion (TCD) graft was given to 62% of patients, post-transplant cyclophosphamide (PTCy) to 17%, and 87% received peripheral blood stem cells (PBSC). Most patients (66%) and donors (54%) were cytomegalovirus (CMV) positive. Median follow-up of alive patients was 30 months (IQR 28-32). Results: We compared changes in patient and transplant characteristics over time in 688 (38%) patients transplanted between 2012 and 2016 and 1139 (62%) patients transplanted between 2017 and 2021. Patients transplanted in recent years had a shorter follow up, were more likely to have NPM1 mutation, to be MRD positive, to have a higher CI, to receive a transplant from a haploidentical donor, a CMV positive donor, and to receive PBSC and PTCy. For patients with wild-type NPM1, day 100 acute graft-versus-host disease (GVHD) grade II-IV and grade III-IV were encountered in 29% and 11% of patients transplanted in 2021-2016, respectively, and 21% and 7% for patients transplanted in 2017-2021, respectively. The 2-year cumulative incidence of chronic and extensive chronic GVHD were 32% and 16%, respectively for 2012-2016 and 36% and 20%, respectively for 2017-2021. Over time, the 2-year cumulative incidence of relapse (CIR) significantly decreased from 43% to 31% between the two time periods (p<0.04) and non-relapse mortality (NRM) significantly decreased from 14% to 8% (p<0.05). The 2-year leukemia free survival (LFS) and overall survival (OS) significantly improved over time from 54% to 64% (p<0.02) and from 63% to 71% (p<0.05) respectively, whereas GVHD-free, relapse-free survival (GRFS) improved from 39% to 46% (p=0.08). In multivariate Cox analysis (MVA), transplantation in recent years significantly reduced the CIR (hazard ratio [HR]=0.65; p<0.01), and acute GVHD grade II-IV (HR=0.6; p<0.01) and significantly improved LFS (HR=0.67; p=0.02), OS (HR=0.66; p<0.03), and GRFS (HR=0.77; p<0.05). The use of unrelated donors increased the risk of acute GVHD but reduced the CIR whereas the use of haploidentical donors increased NRM. In vivo TCD reduced the risk of chronic GVHD whereas female donors to male recipients increased it. PTCy decreased the risk of NRM whereas MAC reduced the CIR. For patients with NPM1 mutation, no significant changes over time in post-transplant outcomes were noted except for decreased NRM from 15% for 217 patients transplanted in 2012-2016, to 10% for 288 patients transplanted in 2017-2021 (p<0.02). In MVA, transplantation in recent years did not significantly affect any of the post-transplant outcomes. Conclusion: In AML patients with FLT3 ITD and wild-type NPM1, we noticed a significant decrease over time in the CIR and a significant improvement of LFS, OS and GRFS, likely reflecting the efficacy of FLT-3 inhibitors, including when used as post-transplant maintenance, in this high-risk setting. On the contrary, no significant change over time was noticed in post-transplant outcomes of patients harboring NPM1 mutation.

Budget Impact Analysis of the Use of Gilteritinib for the Treatment of Patients with Relapsed or Refractory FLT3+ Acute Myeloid Leukaemia in Public Healthcare Institutions in Mexico

INTRODUCTION: More than a third of patients with acute myeloid leukaemia (AML) have mutations in the FMS-like tyrosine kinase 3 gene (FLT3+). Patients with these mutations have a poor prognosis and are at high risk of refractory AML or treatment failure and relapse. In the last few years there have been several advances in treatment options available for relapsed/ refractory (R/R) FLT3+ AML patients, including gilteritinib. Although gilteritinib has demonstrated clinical efficacy in clinical trials, it has higher drug acquisition costs and the economic impact of including it as a new therapy is uncertain. This study aims to estimate the budget impact of the introduction of gilteritinib as an additional AML treatment on the public healthcare system in Mexico. METHODS: The target population (adult AML patients with R/R FLT3+) was calculated assuming an incidence rate of 1/100,000 and 25/100,000 in individuals 18-79 years and 80+ years respectively, 57% of patients would be R/R and 33% FLT3 positive, 2% undergo haematopoietic stem-cell transplantation (HCST), and 72% have their treatment costs covered by public funding. The cost of current AML treatment (mitoxantrone, etoposide and cytarabine [MEC], and/or fludarabine, cytarabine, granulocyte-colony stimulating factor and idarubicin [FLAG-IDA]) was obtained from the Institute for Social Security and Services for State Workers in 2021. Costs were converted to 2022 costs using the Mexican inflation rate, and compared for the following 5 years (assuming 2022 costs remained unchanged), when including gilteritinib as an additional treatment regimen for AML. The budget impact analysis over a 5-year time horizon, included direct drug costs, post-progression treatment costs, resource utilization, HSCT, and grade ≥3 adverse events. All costs were converted to USD (1 USD=20.55 MxP). RESULTS: Based on 2023 population estimates of a total 198 FLT3+ R/R AML patients, the projected consolidated treatment cost per patient is $36,848, $38,041, and $59,621 for MEC, FLAG-IDA and gilteritinib, respectively. When incorporated into a yearly estimate over 5 years, the addition of gilteritinib as a treatment option would result in a spending increase of $109,397 in 2023 rising to $475,761 in 2027. This would be an increase on the public healthcare budget of 0.0024% in 2023 to 0.0105% in 2027. CONCLUSION: Introducing gilteritinib as an orphan drug in Mexico for the treatment of R/R FLT3+ AML would have a minimal impact on the public healthcare budget over the next 5 years.

Venetoclax combined with low dose cytarabine compared to standard of care intensive chemotherapy for the treatment of favourable risk adult acute myeloid leukaemia (VICTOR): Study protocol for an international, open-label, multicentre, molecularly-guided randomised, phase II trial

BackgroundFor patients with acute myeloid leukaemia (AML), the only potentially curative treatment is intensive chemotherapy (IC). This is highly toxic, particularly for patients > 60 years, potentially leading to prolonged hospitalisations requiring intensive supportive care, and sometimes treatment-related death. This also results in extensive healthcare costs and negatively impacts quality of life (QoL). Venetoclax with low-dose cytarabine (VEN + LDAC) is a novel, low-intensity treatment for AML patients who cannot receive IC. VEN + LDAC is given as an outpatient and toxicity appears significantly lower than with IC. Analysis of clinical trials performed to date are promising for patients with the genotype NPM1mutFLT3 ITDneg, where remission and survival rates appear comparable to those achieved with IC.MethodsVICTOR is an international, two-arm, open-label, multi-centre, non-inferiority, randomised-controlled phase II trial to assess VEN + LDAC compared to standard of care (IC) as first-line treatment in older patients (initially aged ≥ 60 years) with newly diagnosed AML. The trial will recruit patients with a NPM1mutFLT3 ITDneg genotype; those with a favourable risk in relation to the experimental treatment. University of Birmingham is the UK co-ordinating centre, with national hubs in Aarhus University Hospital, Denmark, and Auckland District Health Board, New Zealand. The primary outcome is molecular event-free survival time where an event is defined as failure to achieve morphological complete response (CR) or CR with incomplete blood count recovery after two cycles of therapy; molecular persistence, progression or relapse requiring treatment change; morphological relapse, or; death. Secondary outcomes include cumulative resource use at 12- and 24-months, and QoL as assessed by EORTCQLQ-C30 and EQ-5D-3L at 3-, 6-, 12-, 18- and 24-months. The trial employs an innovative Bayesian design with target sample size of 156 patients aged > 60 years.DiscussionThe principle underpinning the VICTOR trial is that the chance of cure for patients in the experimental arm should not be compromised, therefore, an adaptive design with regular checks on accumulating data has been employed, which will allow for a staged expansion of the trial population to include younger patients if, and when, there is sufficient evidence of non-inferiority in older patients.Trial registrationEudraCT: 2020–000,273-24; 21-Aug-2020.ISRCTN: 15,567,173; 08-Dec-2020.

Peripheral levels of monocytic myeloid-derived suppressive cells before and after first induction predict relapse and survivals in AML patients.

Myeloid Derived Suppressive Cells (MDSC) are capable to suppress innate and adaptive immune responses, thus favouring solid cancer progression. However, little is known about the role of MDSC in acute myeloid leukaemia (AML). In this monocentric prospective study, 73 adult AML patients, eligible for first-line intensive chemotherapy, were included with the aim to study the influence on long-term outcomes of peripheral blood (PB) levels of monocytic (M) MDSC (M-MDSC) assessed by flow cytometry. A percentage of peripheral M-MDSC higher than 0.55% of leukocytes at diagnosis and a decrease of M-MDSC% after induction came out both as independent negative prognostic factors for leukaemia-free and overall survival.

Targeting CD38 for acute leukemia.

Acute leukemia (AL) is a hematological malignancy, and the prognosis of most AL patients hasn’t improved significantly, particularly for relapsed or refractory (R/R) AL. Therefore, new treatments for R/R adult acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) are urgently necessary. Novel developments have been made in AL treatment, including target and immune therapies. CD38 is one of the targets due to its high expression in many hematological malignancies, including multiple myeloma, ALL and a subset of AML. Consequently, targeting CD38 therapies, including CD38 monoclonal antibodies (mAbs), bispecific antibodies, and CAR-T cell therapy, exhibit promising efficacy in treating multiple myeloma without significant toxicity and are being explored in other hematological malignancies and nonhematological diseases. Herein, this review focuses on targeting CD38 therapies in ALL and AML, which demonstrate sound antileukemic effects in acute leukemia and are expected to become effective treatment methods.

Thymic adenocarcinoma presenting as an incidental mediastinal mass

BackgroundPrimary thymic adenocarcinoma represents an exceptionally rare malignancy, for which the cornerstone of therapy is margin-negative resection, with radiation and systemic therapy reserved for invasive and advanced disease. Thymic adenocarcinoma has not been previously reported in the setting of a concomitant malignancy, as reported herein.Case presentationWe present a case of a 55-year-old previously healthy male diagnosed with acute myeloid leukemia, also found to have a mediastinal mass. Evaluation of the mediastinal mass with tumor markers, biopsies, and next-generation sequencing proved non-diagnostic, while he was simultaneously treated with induction chemotherapy to prevent leukemia-related blast crisis. After completing and recovering from induction chemotherapy, he underwent successful thymectomy during a chemotherapy holiday, with a margin-negative resection of thymic adenocarcinoma. He has subsequently recovered and undergone successful allogeneic hematopoietic stem cell transplant.ConclusionsWe present a case of synchronous adult acute myeloid leukemia and primary thymic adenocarcinoma requiring a tailored approach for management of simultaneous malignancies.

Cytogenetic profile of adult acute myeloid leukemia in Egypt: a single-center experience

BackgroundAcute myeloid leukemia (AML) is a diverse disease characterized by the expansion of blasts of myeloid lineage. Cytogenetic testing is the cornerstone for risk stratification of AML patients. Geographical and environmental factors may play a very important role in the development of leukemia and several differences in genetic profile may be seen among different ethnicities. In our study, we evaluated cytogenetic findings of adult AML patients in South Egypt.MethodsCytogenetic testing (karyotyping and M-FISH) was performed for 120 adult patients with AML. Twenty metaphases were analyzed for each patient.ResultsIn our study, the median age of AML patients was 36.5 years, with an age range between 18 and 86 years. 56.7% of patients had normal karyotypes and 43.3% of patients had clonal cytogenetic abnormalities. t (15;17) was the most detected structural abnormality, and + 8 was the most detected numerical abnormality. Regarding cytogenetic risk stratification, 65% of patients were in the intermediate-risk category.ConclusionThe cytogenetic profile of AML patients in our locality showed some differences and some similarities with cytogenetic profiles in different Arab, Asian and Western countries. Further studies are needed using advanced techniques such as next-generation sequencing and optical genome mapping to elucidate more ethnic and geographic genetic heterogeneity among different countries.

Description of a novel subtype of acute myeloid leukemia defined by recurrent CBFB insertions

Description of a novel subtype of acute myeloid leukemia defined by recurrent CBFB insertions

AML-341 The Cytogenetic Profile of Adult Acute Myeloid Leukemia in Morocco

Acute myeloid leukemia (AML) represents 1% of cancers and 80% of leukemia cases in adults, with an incidence that increases with age. AML is characterized by cytological and cytogenetic clinical heterogeneity. Examining the karyotype is essential during the evaluation of AML at diagnosis because the detection of cytogenetic abnormalities constitutes one of the most powerful independent prognostic factors for this pathology and serves as an integral component of the choice of therapeutic strategy. The aim of our study is to evaluate the profiles of patients with AML in Morocco. A retrospective study was conducted from January 2014 to December 2018, including patients aged 18 and older diagnosed with AML. Data were collected from patient medical records and the cytogenetic database. Prognostic groups were determined according to the ELN 2017 classification. Of 309 patients diagnosed with AML, cytogenetic studies were successfully performed in 261 patients (85.5%). Chromosomal abnormalities were found in 161 patients, resulting in 21.07% of patients classified as favorable, 58.6% as intermediate, and 20.3% as unfavorable. A normal karyotype was the most frequently found, in 38% of patients, followed by a complex karyotype in 12.6%. AML CBF accounted for 12% of cases. Molecular biology was studied in 47 patients (15.2%), resulting in a change in prognostic classification for 11 patients, 8 of whom were reclassified from intermediate to favorable, and 3 of whom were reclassified from intermediate to unfavorable. The mutations associated with AML have continued to increase in recent years due to advancements in laboratory tools. Molecular biology must be an integral component of the AML diagnosis in our practice in order to improve the therapeutic management of the different prognostic groups.

AML-143 Trial in Progress: Phase Ib/II Study of Siremadlin in Combination With Venetoclax + Azacitidine in Patients With Acute Myeloid Leukemia (AML) Who Are Ineligible for Intensive Chemotherapy (IC)

Treatments for AML patients unfit for IC are limited. Venetoclax+hypomethylating agents (HMAs) demonstrated improved survival; however, relapse rates are high, and most patients remain measurable residual disease (MRD) positive. Siremadlin is a selective inhibitor of the tumor protein 53 (p53)-murine double minute-2 (MDM2) interaction. AML patients treated with siremadlin experienced a tolerable safety profile and preliminary antitumor activity in a Phase I study (NCT02143635). Initial results from a Phase lb study exploring siremadlin+venetoclax showed promising antileukemic activity in patients with relapsed/refractory AML (NCT03940352). To describe the study design of a Phase lb/II study assessing the safety and efficacy of siremadlin+venetoclax+azacitidine in AML patients unfit for IC (NCT05155709). The study will consist of a safety run-in (part 1) and an expansion phase (part 2). Adult AML patients unfit for IC due to age (≥75 years) or comorbidities are eligible. Patients with TP53 mutation or del17p are excluded. Two subpopulations will be evaluated: patients with prior suboptimal response (no CR, CRh, CRi, or morphologic leukemia-free state) after 2-4 cycles of first-line venetoclax+azacitidine (Arm 1) and patients with newly diagnosed AML with high-risk features that confer a low likelihood of response to venetoclax+HMAs (adverse genetic risk stratification per European Leukemia Network, 2017; Arm 2). Safety run-in/part 1: siremadlin 20 or 30 mg from Day (D)1 to D5 in each 28-day cycle with venetoclax+azacitidine. Arm 1: patients will continue receiving their tolerated venetoclax+azacitidine doses prior to study enrollment. Arm 2: venetoclax will be increased over 3 days to a target daily dose of 400 mg and azacitidine (75 mg/m2) from D1-D7 or from D1-D5, and D8+D9. Upon confirmation of the recommended dose for expansion (RDE) for each arm, enrollment for the expansion phase/part 2 will open; patients will be treated with siremadlin at the RDE in combination with venetoclax+azacitidine. Primary endpoints: incidence of dose-limiting toxicities (Arms 1 and 2 separately) and CR rate (Arm 1). Secondary endpoints: safety and tolerability; CR rate (Arm 2); CR/CRh and CR/CRi rates, duration of CR, CRi, and CRh; OS; early mortality; MRD; pharmacokinetics.

AML-377 A “Designed” High-Throughput Drug Screening Strategy Identifies Aurora Kinase A Inhibitors as Promising Preclinical Candidates for the Treatment of NPM1-Mutated AML

Nucleophosmin (NPM1)-mutated acute myeloid leukemia (AML) accounts for one-third of adult AML and displays distinctive biological and clinical features. Despite its chemo-sensitivity and a relatively favorable prognosis, this leukemia lacks any specific therapies. Because NPM1 mutant protein is not druggable, targeting its non-oncogene addictions and its specific vulnerabilities can represent an alternative option for identifying a tailored therapy for NPM1-mutated AML. We performed a high-throughput screening (HTS) of different chemical compounds and drug libraries to find drugs or compounds 'synthetically lethal' with NPM1 mutation and/or showing more selective activity in AML with NPM1 mutation. In collaboration with the Screening Unit of Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP; (Berlin, Germany), we performed an HTS of 38720 drugs/compounds in a 384-well format. The assay readout was cellular metabolism/viability by CellTiter Blue assay at 48 hours. The screening was properly designed in 2 steps to increase efficiency, exclude compounds with general toxicity, and identify compounds ('hits') selectively active against the only two available NPM1-mutated AML cell lines, OCI-AML3 and IMS-M2, but not against wild-type controls. Sixty-two hit compounds that met qHTS threshold criteria were rescreened in a dose-response experiment. From this analysis, we obtained 37 compounds able to selectively kill IMS-M2 (IMS-M2 %viability <50 vs. OCI-AML2 %viability >75). We focused on Aurora kinase A inhibitors (AURKAi) because 4 of the selective compounds were directed against this kinase. In the validation assay, 2 compounds (MK-5108 and MK-8745) were confirmed as more active against NPM1-mutated than NPM1-wild-type AML cells by either CyQUANT or apoptosis assay. Strikingly, we confirmed selectivity for two additional AURKAi (Alisertib and ENMD-2076, both isoform-selective inhibitors of AURKA) that were not included in the screening library. The AURKAi were also effective in reducing tumor burden in NPM1-mutated PDX cell models and provided a survival advantage compared with vehicle-treated mice (60 vs. 32 days, P=0.005). We demonstrated that using HTS can considerably shorten drug discovery time scales, leading to the identification of promising lead compounds. Our study is the first to provide preclinical evidence of the antileukemic activity of AURKAi, with particular focus on NPM1-mutated AML.

Intensified cytarabine dose during consolidation in adult AML patients under 65 years is not associated with survival benefit: real-world data from the German SAL-AML registry

PurposeHigher doses of cytarabine appear to improve long-term outcome in acute myeloid leukemia (AML), in particular for younger patients. To this end, the optimal dosage of single-agent cytarabine in consolidation therapy remains elusive. Here, we assessed the impact of different dosages of cytarabine consolidation after 7 + 3 induction on outcome in a large real-world data set from the German Study Alliance Leukemia-Acute Myeloid Leukemia (SAL-AML) registry.MethodsPatients between 18 and 64 years of age, registered between April 2005 and September 2020, who attained complete remission after intensive induction and received at least one consolidation cycle with intermediate (IDAC) or high-dose cytarabine (HiDAC) were selected. To account for differences in patient and disease characteristics between both groups, the average treatment effect was estimated by propensity score weighting.ResultsSix-hundred-forty-two patients received HiDAC consolidation with median dosage of 17.6 (IQR (interquartile range), 16.5–18.0) g/m2 for a median number of 3 cycles (IQR, 2–3), whereas 178 patients received IDAC consolidation with 5.9 (IQR, 5.7–8.6) g/m2 for a median of 2 cycles (IQR, 1–3). Both groups differed significantly in some important characteristics (age, sex, cytogenetic risk group, ECOG performance status, disease status, HCT-CI, number of induction cycles). After propensity score weighting for differences in patient and disease characteristics, relapse-free survival after 2 years was comparable between HiDAC-treated (55.3%) and IDAC-treated (55.6%) patients (HR = 0.935, p = 0.69). Moreover, no significant differences in overall survival were observed after 2 years (84.7 vs. 80.6%, HR = 1.101, p = 0.65). Notably, more patients treated with IDAC received allogeneic hematopoietic cell transplantation in first remission (37.6 vs. 19.8%, p < 0.001). Censoring for allogeneic hematopoietic cell transplantation in first remission revealed no significant survival difference with regard to cytarabine dosage. Considering only of European LeukemiaNet (ELN) favorable-risk AML patients, there was no significant difference in outcome. Of note, significantly more patients treated with HiDAC suffered from ≥ 3 CTCAE infectious complications (56.7 [95%-CI 52.8–60.6%] vs. 44.1% [95%-CI 36.6–51.7%]; p = 0,004). The rate of other ≥ 3 CTCAE non-hematological toxicities and secondary malignancies was comparable in both treatment groups.ConclusionsThis retrospective analysis suggests no significant benefit of high-dose cytarabine compared to intermediate dosages in consolidation for AML patients under 65 years of age, independent of ELN risk group.Trial registrationNCT03188874.

T cell receptor excision circles are potential predictors of survival in adult allogeneic hematopoietic stem cell transplantation recipients with acute myeloid leukemia.

BackgroundLymphocyte neogenesis from primary lymphoid organs is essential for a successful reconstitution of immunity after allogeneic hematopoietic stem cell transplantation (HSCT). This single-center retrospective study aimed to evaluate T cell receptor excision circles (TREC) and kappa-deleting recombination excision circles (KREC) as surrogate markers for T and B cell recovery, as predictors for transplantation-related outcomes in adult acute myeloid leukemia (AML) patients.MethodsNinety adult patients diagnosed with AML and treated with HSCT between 2010 and 2015 were included in the study. TREC and KREC levels were measured by quantitative PCR at 1, 3, 6, and 12 months after transplantation.ResultsOverall, excision circle levels increased between 3 and 6 months post-HSCT for TREC (p = 0.005) and 1 and 3 months for KREC (p = 0.0007). In a landmark survival analysis at 12 months post-HSCT, TREC levels were associated with superior overall survival (HR: 0.52, 95% CI: 0.34 - 0.81, p = 0.004). The incidence of viral infections within the first 100 days after transplantation was associated with lower TREC levels at 6 months (p = 0.0002). CMV reactivation was likewise associated with lower TREC levels at 6 months (p = 0.02) post-HSCT. KREC levels were not associated with clinical outcomes in statistical analyzes.ConclusionsResults from the present study indicate that TREC measurement could be considered as part of the post-HSCT monitoring to identify AML patients with inferior survival after transplantation. Further prospective studies are warranted to validate these findings.

P244 Catheter-associated blood stream infections due to Wickerhamiella pararugosa in a patient with acute myeloid leukemia: Review of lit eratures

Poster session 2, September 22, 2022, 12:30 PM - 1:30 PM ObjectivesThis report aims to present a case of Candida pararugosa bloodstream infection, review previous cases with C. pararugosa infections, and provide a concise review of the clinical background, risk factors, and brief the management of infections.MethodsA 3-year-old boy with a history of acute myeloid leukemia was hospitalized in Omid Hospital, Isfahan, Iran. Two consecutive blood cultures were taken from the peripheral vein and port catheter; after that empirically meropenem was administered.Results Candida pararugosa were isolated from blood based on conventional and molecular assays. Furthermore, the antifungal susceptibility profiles of the isolate were determined, which exhibited resistance to fluconazole (8 μg/ml). Antifungal therapy with caspofungin and removing the patient's port led to a significant clinical improvement of the patient's conditions. So far, in the literature review, 10 cases of clinical C. pararugosa isolates were found, of which 5 points had bloodstream infections.ConclusionInfections caused by uncommon Candida species have dramatically increased in recent decades, mostly among hematological malignancies. Most patients with C. pararugosa infection presented with specific underlying conditions, such as malignancy, sarcoma, surgery, and adult acute myeloid leukemia. Patients with indwelling catheters run a high risk of acquiring C. pararugosa bloodstream infection. Therefore, special consideration should be given to opportunistic fungal infections in immunocompromised individuals using catheters.

Effects of chemotherapy dose reductions in overweight patients with acute myeloid leukaemia: A Danish nationwide cohort study.

Overweight patients with cancer are frequently reduced in chemotherapy dose due to toxicity concerns, although previous studies have indicated that dose reduction (DR) of overweight patients results in comparable toxicity but may compromise overall survival (OS). Current evidence regarding DR in patients with acute myeloid leukaemia (AML) is limited. To investigate the association between DR and outcome among overweight patients with AML we analysed a Danish nationwide cohort of overweight adult AML patients treated with remission induction chemotherapy. Among 536 patients identified, 10.1% were categorized as DR defined as 95% or less of full body surface area (BSA)-based dose. Risk factors for DR were high body mass index (BMI) and BSA, therapy-related AML and favourable cytogenetics. No significant differences were observed for rates of complete remission (CR), 30- and 90-day mortality between DR and non-DR patients. Furthermore, DR did not affect median relapse-free survival (RFS) [DR, 14.5 (95% confidence interval, 9.0-41.7) months; non-DR, 15.0 (12.3-19.3)] with an adjusted difference in five-year restricted mean survival time (Δ5y-RMST) of 0.2 (-8.4 to 8.8) months nor median OS (DR, 17.0 [11.9 to 45.5] months; non-DR, 17.5 [14.8 to 20.5]) with an adjusted Δ5y-RMST of 0.8 (-5.7 to 7.3) months. In conclusion, we found no statistically significant association between DR and outcomes among overweight patients with AML. However, we acknowledge the limited sample size and encourage further studies in this important subject.

Frequency and clinical impact of WT1 mutations in the context of CEBPA-mutated acute myeloid leukemia

ABSTRACT Introduction Several studies have confirmed that mutations in the Wilms tumor 1 (WT1) gene occur in adult acute myeloid leukemia (AML). However, few data are available regarding the incidence of WT1 mutations in CEBPAmut AML and their impact. Methods We retrospectively analyzed the frequency and clinical impact of WT1 mutations in 220 newly diagnosed AML patients with CEBPA mutations(CEBPAmut). Chromosome karyotype analysis was performed by R or G banding method and further confirmed either by fluorescence in situ hybridization (FISH) and/or by multiple reverse transcription polymerase chain reaction (multiple RT–PCR). Mutations were detected with a panel of 112mutational genes using next-generation sequencing (NGS). Results Overall, 30 WT1 mutations were detected in 29 of the 220 CEBPAmut AML patients (13.18%) screened. These mutations clustered overwhelmingly in exon 7 (n=16). WT1 mutations were found to be significantly more frequent in AML patients with double-mutated CEBPA (CEBPAdm) than in AML patients with single-mutated CEBPA (17.36%vs. 8.08%, P = 0.043). Among WT1-mutated patients, the most common co-mutation was FLT3-ITD (n = 7, 24.14%), followed by NRAS (n = 5, 17.24%), CSF3R (n = 4, 13.79%), GATA2 (n = 4, 13.79%), and KIT (n = 4, 13.79%). The most frequent functional pathway was signaling pathways inas many as 62.07% of cases. Notably,the concomitant mutations in epigenetic regulatorswere inversely correlated with WT1 mutations(P = 0.003). CEBPAdm AML patients with WT1 mutations had inferior relapse-free survival, event-free survival and overall survival compared with patients CEBPAdm AML without WT1 mutations (P = 0.002, 0.004, and 0.010, respectively). Conclusion Our data showed that WT1 mutations are frequently identified in CEBPAmut AML, especially in CEBPAdm AML. CEBPAmut AML patients with WT1 mutations show distinct spectrum of comutations. In the context of CEBPAdm AML, WT1 mutations predict a poor prognosis.

Retraction: The lnc-SNHG1 Gene Is Overexpressed and Correlates with Increased White Blood Cell Count, Poor Induction Treatment Response, and Poor Survival Profile in Adult Acute Myeloid Leukemia

Objective: Long noncoding RNA small nucleolar RNA host gene 1 (lnc-SNHG1) is involved in leukemogenesis via mediating multiple pathways. The current study aimed to further explore its clinical roles in disease risk, clinical features, and prognosis in patients with acute myeloid leukemia (AML).Materials and Methods:A total of 161 adult AML patients, 50 patients as a disease control (DC) group, and 50 healthy individuals as a healthy control (HC) group were enrolled and bone marrow mononuclear cells were collected. Subsequently, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was performed to measure lnc-SNHG1 expression.Results: Lnc-SNHG1 expression was higher in AML patients than in the DC and HC groups (both p<0.001), with good value in distinguishing AML patients from DC and HC individuals (area under the curve of 0.726 and 0.884, respectively). Moreover, lnc-SNHG1 expression was positively associated with white blood cell (WBC) count (p=0.008) but was not correlated with other clinical features such as cytogenetics, molecular genetics, and risk stratification (all p>0.05). Lnc-SNHG1 expression was also associated with a lower complete remission (CR) rate (p=0.001). Patients with lnc-SNHG1 expression in the fourth quantile had the worst CR rates compared to patients with lnc-SNHG1 expressions in the first, second, and third quantiles (all p<0.05). Furthermore, lnc-SNHG1 expression was correlated with unsatisfactory event-free survival (p<0.001) and overall survival (p=0.002), which were worst in patients with lnc-SNHG1 expression in the fourth quantile compared to patients with lnc-SNHG1 expressions in the first, second, and third quantiles (all p<0.05).Conclusion: Lnc-SNHG1 overexpression is associated with elevated WBC count, poor induction treatment response, and poor survival profile in cases of AML and it may serve as a potential indicator for AML.

Reducing Mortality of Single-Unit Unrelated Cord Blood Transplantation for Relapsed Acute Myeloid Leukemia after a Previous Allogeneic Transplantation: A Real-World Retrospective Study Over the Past 19 Years in Japan

Relapse is the most common cause of treatment failure after allogeneic hematopoietic cell transplantation (HCT) for acute myeloid leukemia (AML). Second or subsequent allogeneic HCT using unrelated cord blood has been performed for adult patients with AML who have relapsed after a previous allogeneic HCT. Although outcomes after unrelated cord blood transplantation (CBT) as the first allogeneic HCT have significantly improved in recent years, it is unclear whether survival and engraftment improve after CBT as the second or subsequent allogeneic HCT for adult AML patients relapsing after a previous allogeneic HCT. The objective of this retrospective study was to evaluate trends of survival and other transplantation outcomes after single-unit unrelated CBT as a second or subsequent allogeneic HCT in adult patients with relapsed AML after a previous allogeneic HCT over the past 19 years in Japan. We retrospectively assessed survival trends and other outcomes of single-unit unrelated CBT as a second or subsequent allogeneic HCT in adult patients with relapsed AML after a previous allogeneic HCT according to the time period of CBT (2001-2007, 2008-2013, or 2014-2019) using a nationwide Japanese database. The median age was 45 years among 1109 CBTs, and 844 (78.6%) patients were not in complete remission at the time of CBT. Over the 3 time periods, there was a progressive increase in higher cryopreserved cord blood total nucleated cell dose and myeloablative conditioning regimens. The 2-year overall survival was 14.0% in 2001-2007, 19.9% in 2008-2013, and 24.4% in 2014-2019 (P <.001 by log-rank trend test). The 2-year relapse-related mortality was 54.0% in 2001-2007, 44.4% in 2008-2013, and 39.1% in 2014-2019 (P < 0.001 by Gray's test), but nonrelapse mortality was not significantly different across the time periods (P=0.557 by Gray's test). The 42-day neutrophil engraftment also significantly improved (62.9% in 2001-2007, 69.7% in 2008-2013, and 79.9% in 2014-2019; P < 0.001 by Gray's test). Our data demonstrate significant improvements in overall and relapse-related mortality, as well as neutrophil engraftment, after single-unit unrelated CBT as a second or subsequent allogeneic HCT for adult patients with AML relapsed after previous allogeneic HCT over the past 19 years.