Treatment Of Myeloid Leukemia Research Articles

Advancements in Myeloid Leukemia Treatment: A Comprehensive Update

This comprehensive update explores the recent advancements in the treatment landscape of myeloid leukemia. Myeloid leukemia, a heterogeneous group of hematological malignancies, poses significant challenges in clinical management. This review highlights the latest therapeutic approaches, including targeted therapies, immunotherapies, and emerging treatment modalities. It discusses the impact of precision medicine, novel drug developments, and the evolving role of immunotherapy in managing myeloid leukemia. Furthermore, the abstract outlines current research trends, challenges, and future prospects, aiming to provide a concise overview for healthcare professionals and researchers involved in leukemia management. Keywords: targeted therapy; immunotherapy; precision medicine; molecular profiling; personalized treatment; bone marrow transplantation; novel therapies

Precision Deuteration in Search of Anticancer Agents: Approaches to Cancer Drug Discovery.

Cancer chemotherapy has been shifted from conventional cytotoxic drug therapy to selective and target-specific therapy after the findings about DNA changes and proteins that are responsible for cancer. A large number of newer drugs were discovered as targeted therapy for particular types of neoplastic disease. The initial discovery includes the development of the first in the category, imatinib, a Bcr-Abl tyrosine kinase inhibitor (TKI) for the treatment of chronic myelocytic leukemia in 2001. But the joy did not last for long as the drug developed a point mutation within the ABL1 kinase domain of BCR-ABL1, which subsequently led to the discovery of many other TKIs. Resistance was observed for newer TKIs a few years after their launching, but the use of TKIs in life-threatening cancer therapy is considered as far better compared with the risks of disease because of its target specificity and hence less toxicity. In search of a better anticancer agent, the physiochemical properties of the lead molecule have been modified for its efficacy toward disease and delay in the development of resistance. Deuteration in the drug molecule is one of such modifications that alter the pharmacokinetic properties, generally its metabolism, as compared with its pharmacodynamic effects. Precision deuteration in many anticancer drugs has been carried out to search for better drugs for cancer. In this review, the majority of anticancer drugs and molecules for which deuteration was applied to get better anticancer molecules were discussed. This review will provide a complete guide about the benefits of deuteration in cancer chemotherapy.

T cells with split CARs specific for NKG2D ligands and PD-L1 exhibit improved selectivity towards monocyte-derived cells while effective in eliminating acute myeloid leukaemia in vivo.

The expression of NKG2D ligands and PD-L1 has been detected on acute myeloid leukaemia (AML) cells, as well as normal cells of the myeloid lineage. To target leukemic cells while minimizing collateral damage to normal cells, we constructed a split dual CAR system based on the AND-gate logic. The NKG2D extracellular domain linked with DAP12 without a co-stimulatory signal was used for the basal activation of T cells, and used together with the PD-L1-specific chimeric costimulatory receptor containing the 4-1BB activating domain for co-stimulatory signal 2 input. This dual CAR displayed cell-type specificity and activity similar as a 2nd generation NKG2D ligand-specific CAR. When compared to CD64 and PD-L1-specific 2nd generation CARs, we observed that the split dual CAR offered an improved myeloid cell type selectivity. For example, PD-L1-specific CAR-T cells lysed all tested myeloid cell types that expressed PD-L1, including M0 macrophages (Mø0), LPS-polarized Mø1, IFN-γ polarized Mø1, IL-4 polarized Mø2, monocytes, immature dendritic cells (imDCs), mature DCs, as well as KG-1 AML cells, while the dual CAR-T cells displaying killing activity only towards LPS polarized Mø1, mature DCs and KG-1 cells that expressed both NKG2D ligands and PD-L1. In a mouse liquid tumor model, the dual CAR-T cells were effective in eradicating established KG-1 AML xenografts. The improved cell type specificity offered by our split dual CAR-T cell system targeting paired antigens would favour the reduction of the on-target off-tumor toxicity towards normal myeloid cells during the treatment of myeloid leukaemia.

Homoharringtonine is synergistically lethal with BCL-2 inhibitor APG-2575 in acute myeloid leukemia

BackgroundDespite advances in targeted agent development, effective treatment of acute myeloid leukemia (AML) remains a major clinical challenge. The B-cell lymphoma-2 (BCL-2) inhibitor exhibited promising clinical activity in AML, acute lymphoblastic leukemia (ALL) and diffuse large B-cell lymphoma (DLBCL) treatment. APG-2575 is a novel BCL-2 selective inhibitor, which has demonstrated anti-tumor activity in hematologic malignancies. Homoharringtonine (HHT), an alkaloid, exhibited anti-AML activity.MethodsThe synergistic effects of APG-2575 and HHT were studied in AML cell lines and primary samples. MTS was used to measure the cell viability. Annexin V/propidium iodide staining was used to measure the apoptosis rate by flow cytometry. AML cell xenografted mouse models were established to evaluate the anti-leukemic effect of BCL-2 inhibitor, HHT and their combination in vivo. Western blot was used to determine the expression of related proteins.ResultsAPG-2575 showed comparable anti-leukemic effect to the FDA-approved BCL-2 inhibitor ABT-199 in vitro and in vivo. Combined treatment of HHT with APG-2575 synergistically inhibited AML cell growth and engraftment. Mechanistically, HHT promoted degradation of myeloid cell leukemia-1 (MCL-1), which was reported to induce BCL-2 inhibitor resistant, through the PI3K/AKT/GSK3β signaling pathway.ConclusionOur results provide an effective AML treatment strategy through combination of APG-2575 and HHT, which is worthy of further clinical research.

Structure-guided engineering of a flavin-containing monooxygenase for the efficient production of indirubin

Indirubin is a bisindole compound for the treatment of chronic myelocytic leukemia. Here, we presented a structure-guided method to improve the activity of a flavin-containing monooxygenase (bFMO) for the efficient production of indirubin in Escherichia coli. A flexible loop interlocked with the active pocket through a helix and the substrate tunnel rather than the active pocket in bFMO were identified to be two reconfigurable structures to improve its activity, resulting in K223R and N291T mutants with enhanced catalytic activity by 2.5- and 2.0-fold, respectively. A combined modification at the two regions (K223R/D317S) achieved a 6.6-fold improvement in catalytic efficiency (kcat/Km) due to enhancing π–π stacking interactions stabilization. Finally, an engineered E. coli strain was constructed by metabolic engineering, which could produce 860.7 mg/L (18 mg/L/h) indirubin, the highest yield ever reported. This work provides new insight into the redesign of FMOs to boost their activities and an efficient approach to produce indirubin.Graphical

Abstract 3729: Discovery of orally bioavailable SMARCA2/4 dual degraders for treatment of acute myeloid leukemia

Abstract Background: The BAF (SWI/SNF) chromatin remodeling complex comprises of two mutually exclusive ATPases, SMARCA2 (BRM) and SMARCA4 (BRG1), that affect the mobilization and positioning of nucleosomes on DNA and thereby regulates important cellular functions including transcription, DNA recombination, DNA repair and chromosome decatenation during mitosis. SMARCA4 is frequently overexpressed in several types of cancers. Overexpression has been linked to increased proliferation and survival, as well as aggressive tumors and poor prognosis. SMARCA4 knockdown in these tumors lead to inhibition of proliferation and increased sensitivity to known chemotherapeutic agents, supporting the validity of targeting SMARCA4. Genetic silencing studies have established that the oncogenic activity of tumors lacking SMARCA4 is primarily driven by SMARCA2-containing residual SWI/SNF complex, suggesting the importance of dual inhibition of SMARCA2 and SMARCA4. While SMARCA4 is known to play a vital role in maintaining the oncogenic transcription program and driving proliferation in leukemia, the impact of dual SMARCA2 and SMARCA4 inhibition/degradation in acute myeloid leukemia (AML) is largely unexplored. Methods and Results: As part of the initial design plan, selective SMARCA2/4 Bromodomain inhibitors and specific ligands of several E3 ligases were chosen to arrive at different degrader designs. A choice of linkers and different exit vectors were considered to construct a variety of hetero bifunctional molecules. Our proprietary ternary complex modeling algorithm, ALMOND (ALgorithm for MOdeling Neosubstrate Degraders) helped in prioritizing the designs. Short listed compounds were synthesized and profiled in multiple cellular assays to understand their degradation potential. Several compounds that degrade SMARCA2, SMARCA4 & PBRM1 with pico molar DC50 were identified. These compounds have shown very potent anti-proliferative activity in both SMARCA2/4 proficient (MV-4-11, VCaP etc) and SMARCA4 mutant cell lines (SK-MEL-5 & RERF-LC-A1 etc). Further, potent compounds were optimized for their pharmacokinetic properties. Multiple lead compounds with low IV clearance and good oral bioavailability in rodents were identified. Advanced lead compounds are currently being evaluated in rodent tolerability and PK-PD experiments to select doses for the efficacy study. Conclusions: Highly potent degraders of SMARCA2, SMARCA4 & PBRM1 were identified by conjugating selective SMARCA2/4 Bromodomain inhibitors and several E3 ligase specific ligands. Further optimization of the linkers resulted in compounds with improved pharmacokinetic profile and very good oral bioavailability in rodents. Highly potent and orally available degraders of SMARCA2, SMARCA4 are efficacious in AML xenograft models and advanced profiling of candidate molecule is in progress. Citation Format: Chandrasekhar Abbineni, Leena Khare, Bilash Kuila, Abdul Rawoof Khaji, Dhaytadak Bhagwan Mahadeo, Sandeep Vitthal Dukare, Bhagya M S Kumar, Suraj T Gore, Vijay Kamal Ahuja, Amit A Dhudashiya, Raghavendra N R, Nagesh Gowda, Charamanna K B, Kiran Aithal B, Samiulla D S, Subhendu Mukherjee, Thomas Antony, Sanjeev Giri, Shekar Chelur, Kavitha Nellore, Girish Daginakatte, Murali Ramachandra, Susanta Samajdar. Discovery of orally bioavailable SMARCA2/4 dual degraders for treatment of acute myeloid leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3729.

Abstract 553: Combined use of human iPSC-derived natural killer cells with macrophages and anti-CD47 blockade to improve killing of acute myeloid leukemia

Abstract Despite many recent advances, treatment of acute myeloid leukemia (AML) remains challenging. To generate an improved cell-based therapy against AML, our group has produced NK cells from induced pluripotent stem cells (iPSCs). iPSC-derived NK cells effectively kill AML cells, but may benefit from combination with other therapies. Based on studies showing that targeting the CD47 pathway on macrophages (Mϕ) improves anti-tumor activity in AML, we investigated the combination of iPSC-NK cells with iPSC-Mϕ with and without CD47 blockade for the treatment of AML. To determine if the addition of iPSC-Mϕ can improve the cytotoxicity of NK cells against AML blasts, we co-cultured iPSC-NK cells and MOLM13 or MV-4-11 AML cells with iPSC-Mϕ in standard cytotoxicity assays. While Mϕ alone did not kill AML blasts, the addition of iPSC-Mϕ to iPSC-NK cells significantly improved killing of AML blasts by 50% (p<0.01). Addition of an anti-CD47 mAb (B6H12) further increased killing of AML blasts by an additional 23% (p<0.01). Addition of the CD47 mAb to iPSC-Mϕ without NK cells did not result in increased killing. We also demonstrated that blockade of SIRPα (receptor for CD47) significantly increased NK cell killing of AML blasts by 16% (p<0.05). Furthermore, the combination of iPSC-NK cells + iPSC-Mϕ + SIRPα mAb led to a 37% increase in cytotoxicity compared to iPSC-NK cells + iPSC-Mϕ alone (p<0.01). To confirm that addition of anti-CD47 or anti-SIRPα antibodies increased killing via loss of the inhibitory CD47-SIRPα interaction on NK cells and not via another mechanism, we tested the effect of adding anti-CD47 mAb and SIRPα antibodies simultaneously. Compared to addition of either mAb alone, the combination induced no additional increase in anti-AML activity by the NK cells. We also found the addition of the SIRPα mAb to iPSC-Mϕ alone did not increase cytotoxicity. We next evaluated if antibody dependent cellular cytotoxicity (ADCC) mediated by anti-CD47 mAb binding AML cells could account for the increase in cytotoxicity and found that blockade of Fc-receptors on NK cells does not diminish the increase in cytotoxicity, indicating no role for ADCC. Finally, we showed that direct contact between NK cells and Mϕ is required to increase killing of AML in a transwell assay. Separation of iPSC-Mϕ from iPSC-NK cells by a transwell insert abrogated the increase in anti-AML cytotoxicity seen with addition of iPSC-Mϕ to NK cells without the insert. In vivo studies testing the combination of iPSC-NK cells, iPSC-Mϕ and CD47 mAb against human AML in mouse xenograft-models are ongoing. Together our results indicate that CD47 blockade combined with iPSC-Mϕ leads to increased NK cell-mediated anti-tumor activity. iPSC-NK cells and iPSC-Mϕ provide an important, standardized, allogeneic cell therapy approach. Citation Format: Benjamin Goldenson, Manuel Fierro, Somayeh Pouyanfard, Dan S. Kaufman. Combined use of human iPSC-derived natural killer cells with macrophages and anti-CD47 blockade to improve killing of acute myeloid leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 553.

Abstract 1555: circPVT1 and linear PVT1 isoforms regulate cell growth, metabolic and DNA damage response related gene signatures in acute myeloid leukemia

Abstract Non-coding (nc)RNAs, including circular (circ)RNAs, contribute to tumor development and progression. Several ncRNAs were shown to affect the onset, prognosis, and treatment of acute myeloid leukemia (AML) in the past years. The human Plasmacytoma Variant Translocation 1 (PVT1) gene maps on the long arm of chromosome 8 (8q24), in the same genomic region hosting MYC and encoding for 83 linear (PVT1, lncipedia.org) and 26 high-confidence circular isoforms (circPVT1, www.circbase.org). The most common isoform of circPVT1 is a product of back-splicing of 410 nt and contains the whole exon 2 of PVT1 in a closed loop-like structure (hsa_circ_0001821). The study aims to investigate the role of PVT1 isoforms and circPVT1 in AML. Firstly, we focused on the various PVT1 isoforms and their differential expression in leukemia. Fourteen out of the 83 linear isoforms are expressed in the hematopoietic tissues (lymph node and white blood cells, www.noncode.org), and 6 of them were detectable in AML cell lines, including the t(8;21) KASUMI-1 and the NPM1-mutated OCI-AML3 models, together with circPVT1. We designed two antisense-oligonucleotides (ASOs), mapping on common exonic region and targeting the linear isoforms expressed in OCI-AML3 and KASUMI-1 cells, and one ASO spanning the junction region of circPVT1. ASOs-mediated knockdown (KD) showed a relevant decrease of PVT1 signals, especially by ASO combination, and circPVT1 level using the specific ASO in both cell lines, under normoxia and hypoxia (1% O2). The downregulation led to a significant decrease in cell growth, but, interestingly, only circPVT1-KD induced apoptosis under both conditions in OCI-AML3. To further investigate the biological consequences of circPVT1-KD, we performed RNAseq assays. Data analysis was performed by pseudo alignment of paired-end reads to the human transcriptome, then counted with the Kallisto tool. Differential expression analysis of single isoforms was performed with the Sleuth tool on normalized transcript per million. We identified a core of 644 and 838 commonly regulated genes by circPVT1 in both cell lines under normoxia and hypoxia, respectively. Pathway analysis (performed by EnrichR) revealed that these genes are involved not only in the RNA regulatory pathways, as expected according to circRNA functions, but also in metabolic (e.g., KDM3A, GPI, NFKBA, RBM3, XBP1) and DNA damage response (e.g., PIDD1, MUC1, BCLAF1, BABAM2) pathways, opening a new scenario for synthetic lethality approaches. In conclusion, our findings show that silencing of circPVT1 or the predominantly expressed PVT1 isoforms dampens leukemia cell growth, indicating a role in AML pathogenesis, and suggest that targeting them may have therapeutic potentials in AML. Citation Format: Martina Ghetti, Antonella Padella, Eugenio Fonzi, Lorenzo Ledda, Andrea Ghelli Lusernadi Rorà, Matteo Paganelli, Doron Tolomeo, Clelia Tiziana Storlazzi, Giovanni Martinelli, Giorgia Simonetti. circPVT1 and linear PVT1 isoforms regulate cell growth, metabolic and DNA damage response related gene signatures in acute myeloid leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1555.

Abstract 3324: Optimizing the therapeutic potential of tyrosine kinase inhibitors in chemo-immunotherapy of B-cell acute lymphoblastic leukemia involving rituximab

Abstract B-cell acute lymphoblastic leukemia (B-ALL) is a malignancy caused by accumulation of immature B cells. Advances in the field, especially in genomic studies and new treatment development, significantly improved the prognosis of B-ALL over the last decades. However, the B-ALL subtype harboring Philadelphia chromosome t(9;22)(q34;q11) (Ph+ B-ALL) still remains a therapeutic challenge despite available targeted treatment with tyrosine kinase inhibitors (TKIs). The novel therapeutic regimens for adult B-ALL often include rituximab (RTX) - a monoclonal anti-CD20 antibody - for patients with >20% CD20+ blasts. Moreover, drug combinations including approved TKIs and antibodies are being tested in clinical trials. Since some TKIs display immune effector cell inhibition, investigating their immunomodulatory effects in the context of combined chemo-immunotherapies is clinically relevant for the rational combination design. We found that blasts isolated from Ph+ B-ALL patients showed the highest CD20 expression on mRNA level among defined B-ALL genetic subtypes. As Ph+ CD20+ patients may be qualified for treatment with TKIs along with RTX, this result prompted the need of investigating the effects of TKIs on immune effectors. We therefore compared how first-, second- and third-generation TKIs (imatinib, dasatinib, nilotinib, bosutinib, ponatinib) and allosteric inhibitor asciminib recently approved for the treatment of chronic myeloid leukemia (CML) affect innate and antibody-mediated cytotoxicity. B-ALL cell lines, patient-derived lymphoblasts propagated in NSG mice (primografts) and ex vivo whole blood assays were used for testing the efficacy of effector cell-mediated mechanisms in the presence of TKIs. The TKIs were compared in NK-cell based natural cytotoxicity tests, antibody-dependent cytotoxicity (ADCC) tests and phagocytosis assays with monocyte-derived macrophages. Dasatinib was also tested using whole blood ex vivo ADCC assays before and after administration of the TKI. Out of six tested TKIs, asciminib presented the most favorable profile, causing slight or no effector cell inhibition in both innate and antibody-mediated responses. In contrast, dasatinib significantly decreased the immune cells activity in all tests, reducing natural and RTX-mediated cytotoxicity of NK cells against B-ALL blasts. Dasatinib and ponatinib significantly inhibited in vitro phagocytosis of primograft B-ALL cells. To a lesser extent, cytotoxicity and phagocytosis were suppressed by imatinib, bosutinib and nilotinib. Importantly, we confirmed that the orally administered dasatinib impairs the NK cell activity in patients’ blood. Our findings indicate that the TKIs differentially impact RTX-mediated effector mechanisms. The novel, allosteric TKI asciminib could be preferentially used in combination with RTX-based immunotherapy. This work was supported by the Polish National Science Centre grant 2019/35/B/NZ5/01428 and by the Ministry of Education and Science within “Regional Initiative of Excellence” program 013/RID/2018/19." Citation Format: Krzysztof Domka, Martyna Poprzeczko, Zuzanna Urbanska, Lukasz Komorowski, Agata Pastorczak, Klaudyna Fidyt, Agnieszka Dabkowska, Mieszko Lachota, Magdalena Winiarska, Karolina Siudakowska, Elzbieta Patkowska, Łukasz Sędek, Bartosz Perkowski, Beata Krzymieniewska, Malgorzata Firczuk. Optimizing the therapeutic potential of tyrosine kinase inhibitors in chemo-immunotherapy of B-cell acute lymphoblastic leukemia involving rituximab [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3324.

Abstract 3735: Regulation of HPV gene expression by 5-azacytidine treatment in head and neck cancer

Abstract Human papillomavirus (HPV) causes approximately 80% of head and neck squamous cell carcinoma (HNSCC) in the oropharynx, and its incidence is now higher than uterine cervical cancer in the US. The CDC estimates that this common sexually transmitted disease accounts for nearly 13,000 HPV+ HNSCC patients per year in the United States. Despite having a higher cure rate than HPV- HNSCC, the recurrence rate is approximately 30%. These patients have few therapeutic options since resistance to treatment arises from all known therapeutic modalities. Initial therapy for HPV+ HNSCC is aggressive and often results in negative lifelong side effects. The substantial recurrence rate and high morbidity of primary therapy suggest the need for new treatments. Global genome hypermethylation in HPV+ HNSCC, compared to HPV-, prompted our lab to explore demethylation as a therapeutic option. 5-azacytidine (5-aza) and 5-aza-2′-deoxycytidine (decitabine) are synthetic cytidine analogs that cause DNA demethylation by trapping methyltransferases to chromatin. These demethylating agents are FDA approved for the treatment of myelodysplasia and acute myeloid leukemia. Recently, we found that HPV+ HNSCC cells are more sensitive than HPV- cells to 5-aza, that low doses of 5-aza delayed HPV+ xenograft tumor growth, and that HPV+ tumor samples from patients treated with 5-aza in a window trial had increased apoptosis. We also observed a marked downregulation of HPV gene expression after 5-aza. Decreased HPV E6 expression, followed by reactivation of tumor suppressor p53, induced p53-dependent apoptosis in HPV+ HNSCC. Thus, decreased expression of HPV genes is an important component of 5-aza-associated toxicity toward HPV+ HNSCC; therefore, we further explored mechanisms through which demethylation negatively regulates the expression of HPV genes. First, we determined that 5-aza regulates transcription of HPV genes, but not the stability of HPV transcripts. Second, we found that transcriptional regulation of HPV genes after 5-aza depends on the proto-oncogene JunB, a component of the transcription factor Activator Protein 1 (AP-1). Moreover, our experiments revealed that clonogenic survival of HPV+ head and neck cancer cells is dependent on JunB expression. In summary, our study provides an improved mechanistic understanding of the regulation of HPV gene transcription in HNSCC and identifies a novel HPV+ HNSCC dependency on JunB, potentially providing a basis for a new rational targeted therapy. Citation Format: Hina Rehmani, Natalia Isaeva, Wendell G. Yarbrough. Regulation of HPV gene expression by 5-azacytidine treatment in head and neck cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3735.

Re-induction with venetoclax in combination with hypomethylating agents (HMAs) versus FLAG-IDA in relapsed or refractory AML.

e19030 Background: The optimal selection and sequence of salvage regimens during treatment of acute myeloid leukemia (AML) remains unclear. While venetoclax augmentation of a hypomethylating agent backbone is now routinely used as salvage following impressive performance in the front-line setting, little is known about outcomes in relapsed or refractory AML, especially when compared to re-inductions with anthracycline-based regimens. Thus, the aim of this study was to compare outcomes of venetoclax-based regimens versus FLAG-IDA in patients under 70 years. Methods: We retrospectively analyzed 47 patients with AML that were younger than 70 years in the relapsed and refractory setting treated with either FLAG-IDA (fludarabine, cytarabine, G-CSF, and idarubicin) or venetoclax in combination with decitabine or azacitidine from July 2017 to December 2020. Two cohorts were created: a FLAG-IDA cohort and a matched venetoclax cohort for age, ECOG score, and comorbidities. Cytogenetic risk and molecular profiling (through next-generation sequencing [NGS]) at diagnosis and throughout treatment, dates and doses of induction, toxicity, responses, and measurable residual disease (MRD) analysis were recorded and analyzed. Results: In the venetoclax cohort of 32 patients, the median age was 60 years, the median ECOG score was 1, and the median Charlson Comorbidity Index (CCI) score was 4. Six out of 22 evaluable patients achieved either a CR or CRi for a composite response rate (CRR) of 27.3%. Out of three evaluable patients that responded, none were MRD-negative by NGS. The overall survival (OS) of the venetoclax cohort was 8.2 months. In the FLAG-IDA cohort of 15 patients, there were no statistical differences between age (p = .114), ECOG score (p = .249), or CCI score (p = .137) compared to the venetoclax cohort. The CRR of the FLAG-IDA cohort was 85.7%, a significant difference from the venetoclax cohort (p = .011), and 50% were negative for MRD by either NGS or PCR. The overall survival was not reached at a median follow-up time of 15.5 months, significantly different compared to the venetoclax cohort by the log-rank test (p = .001). A Cox proportional hazards model was used to investigate the effects of commonly mutated genes ( NPM1, ASXL1, FLT3, IDH1/2, RAS, TP53, TET2) on OS in venetoclax-based re-induction, and identified IDH1/2 mutations as having a favorable impact in the relapsed/refractory setting (HR 0.01, 95% CI 0.0001-0.7214). Conclusions: Our results highlight the efficacy of FLAG-IDA compared to venetoclax-based regimens with respect to CRR and survival, significantly favoring FLAG-IDA at the time of relapsed or refractory disease. Although limited by sample size, IDH1/2 mutations may convey a better prognosis in the relapsed/refractory setting when treated with venetoclax + HMAs. Larger studies are needed to confirm these findings.

Phase 1B/2A safety, pharmacokinetics, and pharmacodynamics study of fosciclopirox alone and in combination with cytarabine in patients with relapsed/refractory acute myeloid leukemia.

TPS7069 Background: Fosciclopirox (F) is a γ-secretase inhibitor being developed for the treatment of acute myeloid leukemia (AML). Following intravenous (IV) administration, F is rapidly and completely metabolized to its active metabolite, ciclopirox (CPX). CPX binds to γ-secretase complex proteins Presenilin 1 and Nicastrin, which are essential for Notch activation. In HL60 cells, CPX inhibits Notch 1 and Notch 2 expression, reduces levels of γ-secretase complex proteins Presenilin 1 and Nicastrin, and decreases expression of the downstream Notch target gene Hes-1. Utilizing Notable Labs predictive precision medicine platform, bone marrow (BM) and peripheral blood (PB) samples obtained from 10 AML patients treated with CPX demonstrated significant blast count reductions. Methods: Study CPX-POM-003 (NCT04956042) is an open-label Phase 1B/2A, trial designed to characterize the efficacy, safety, and PK/PD of F alone and in combination with cytarabine (ara-C) in patients with relapsed/refractory AML (R/R AML). Eligible patients must be 18 years of age or older with relapsed AML after complete remission or with primary refractory AML refractory to at least two cycles of induction therapy. There will be up to three cohorts of patients, approximately 42 R/R AML patients, evaluated. If disease response to F alone (Cohort 1a) is observed in at least 4 of 14 patients, an additional 14 patients will be enrolled in Cohort 1b. If disease response is not observed following F alone, the study may be terminated or a second cohort, Cohort 2a, may be initiated to evaluate the combination of F + ara-C. If disease response to F + ara-C is observed in at least 4 of 14 patients, an additional 14 patients will be enrolled in Cohort 2b. If response to F + ara-C is not observed in at least 4 of 14 patients, the study will be stopped for futility. F is being administered as 900 mg/m2 once daily as a 20-minute IV infusion on Days 1 to 5 of each 21-day treatment cycle. Ara-C is administered as 1 gm/m2 once daily on Days 1 to 5 of each cycle. BM and PB samples are collected prior to and during Cycles 1 (C1) and 2 (C2) for disease response assessment and blast count determination. Additional BM and PB samples are obtained after every two cycles beyond C2 for patients continuing treatment. Disease response is determined based on Döhner et al, Blood 2017;129(4)424-447. Next Generation Sequencing (NGS) profiles will be determined prior to and at the end of C1, and thereafter as clinically indicated. Immunohistochemistry will be performed on BM samples to elucidate drug mechanism. Ex vivo Drug Sensitivity Screening (DSS) will be performed on BM and PB samples obtained prior to treatment as well as on C1 Days 8 and 21. The steady-state plasma pharmacokinetics of F are being characterized during C1. Enrollment began in October 2022 with four patients enrolled to date. Clinical trial information: NCT04956042.

Imatinib may not be the best choice for planning TFR in CML patients.

e19059 Background: Treatment of chronic myeloid leukemia had been revolutionized by the use of Tyrosine kinase inhibitors. Recently, the strategy of treatment free remission had been introduced to ameliorate toxicity and reduce financial burden beside allowing patients who now have similar survival to normal people to achieve some goals as childbearing. Aim of this study: to check the suitability of imatinib as a first line treatment in potential patients in whom treatment free remission will be an ultimate goal. Methods: This study included patients with chronic myeloid leukemia, chronic phase who were treated in King Abdulla Medical city in the period between 2011 and end of 2019. Initial diagnosis was done by bone marrow, cytogenetics, molecular testing for BCR/ABL. Quantitative estimation of BCR-ABL1 was done on peripheral blood every 3 months to follow response which was assessed according to ELN criteria for follow up. Results: 140 patients were included in this study who received imatinib as first line therapy. The male to female ratio was 1.1 and the median age was 42 Y. 17 patients (12.1 %) were > 60 Y at start of treatment. The majority of patients were considered low risk (70.2%) as by EUTOS risk score. Breakpoint region was e13/a2 in 39.3%, e14/a2 in 38.3% and unknown in 22.7% of patients. 62% of patients were compliant with treatment. At the time of analysis, 79 patients (56%) remained on imatinib. 51/140 (36%) stopped it due to failure, 11 due to intolerance (7.9%). Favorable molecular responses were achieved in 67.4%, 53.9% and 50% at 3,6,12 months respectively. Compliance and risk scores were significantly affecting these responses. 54/70 (77%) of those who achieved MMR at 12 months achieved a deep molecular response (M4, M4.5) after a median period of 36 m. 40 patients (57%,74%) of those who achieved MMR, DMR respectively developed DMR lasting for more than 2 years (which is the requirement for TTF). This also reflects 28.5% of the whole group of patients. Conclusions: Although Imatinib continues to be the preferred first line in treating CML, CP yet it might be more suitable to use a second generation TKI if TFR is planned ahead.

Impact of prior solid tumor on outcomes of allogeneic hematopoietic stem cell transplantation for AML or MDS.

7048 Background: Allogeneic hematopoietic stem cell transplantation (allo-HSCT) offers a definitive treatment of acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). Prior solid tumor (PST) is felt to portend a worse post-transplant prognosis. The aim of this study was to evaluate the impact of PST history on allo-HSCT outcome. Methods: We retrospectively identified patients with AML or MDS who underwent first allo-HSCT at the Fred Hutchinson Cancer Research Center between 2010 and 2018. Cox regression analysis was used to identify factors associated with mortality among patients with PST, and to compare outcomes of patients with and without PST. Multivariable models were fit, adjusting for cytogenetic risk level, time from PST diagnosis to transplant, receipt of reduced-intensity conditioning (RIC), and age at transplant. Survival estimates were obtained using the Kaplan-Meier method. Results: 1198 patients were included for analysis, of which 101 had a history of PST. After a median follow up of 1301 days among survivors, there was a total of 558 deaths and 322 relapses among all patients. Patients with history of PST were older (62.5 vs 54.9 yrs) and a higher proportion received RIC (52.5% vs 27.3%). The most common PSTs included breast (38/101, 38%), prostate (13/101, 13%), colon (9/101, 9%), thyroid (8/101, 8%), and uterine (7/101, 7%). Among those with known staging (n = 66), stage 1 (28/66, 42%) was the most common, followed by stage 2 (17/66, 26%) then stage 3 (15/66, 23%). The most common therapies provided were surgery (95/101, 95%), cytotoxic chemotherapy (41/101, 41%), radiation (45/101, 45%), and endocrine therapy (25/101, 25%). The unadjusted hazard ratio (HR) of mortality in the PST group relative to the non-PST group was 1.10 (95% confidence interval [CI] 0.83-1.47, p = 0.52). After adjustment for patient age, disease, patient/donor CMV status, KPS, cytogenetic risk, source of stem cells, and donor type, the adjusted HR was 0.91 (95% CI 0.68-1.22, p = 0.59). The unadjusted HR for relapse was 1.15 (95% CI 0.79-1.67, p = 0.48), and adjusted HR was 1.11 (0.76-1.11, p = 0.61). Among patients with PSTs, high-risk cytogenetics were associated with increased mortality (adjusted HR = 2.21; 95% CI 1.16-4.2, p = 0.016) and relapse (adjusted HR = 1.91; 95% CI 1.01-3.60, p = 0.047). Longer time from PST diagnosis to transplant led to a numerically increased mortality in the unadjusted (HR = 1.05; 95% CI 1.00-1.11, p = 0.057) and adjusted (HR = 1.05; 95% CI 1.00-1.11, p = 0.69) models treating time as a continuous linear variable. Conclusions: In our study, a history of PST did not impact overall survival or relapse rate among patients who underwent first allo-HSCT for AML or MDS. As in the overall population, post-transplant outcomes were primarily driven by cytogenetic risk level. However, it is likely that selection of patients with PST for transplantation was biased based on overall risk assessment.

Oncology stewardship in acute myeloid leukemia.

In recent years, an explosion of novel agents has shifted the treatment paradigm for patients with acute myeloid leukemia. The optimal place in therapy for many of these novel agents remains unknown due to limited guidance from national guidelines and the way these agents were studied prior to entering the market. A critical evaluation of the literature and incorporation of oncology stewardship principles can be helpful in determining an optimal place for these agents while being mindful of the overall cost that is associated with therapies. The purpose of this review is to critically evaluate the efficacy and safety data for five controversial agents and provide examples of the use of stewardship practices in determining their place in the treatment of acute myeloid leukemia.

Azacitidine and its role in the upfront treatment of acute myeloid leukemia

ABSTRACT Introduction Acute myeloid leukemia (AML) predominantly affects elderly population. This poses challenges in management, as patients are frequently not candidates for intensive therapy given comorbidities or frailty. Currently, azacitidine (AZA), either as monotherapy or in combination regimens, is the backbone treatment in this group of patients. Areas covered We review the mechanism of action, pharmacology, clinical efficacy, and safety of AZA. It reviews current combination therapies of AZA with other targeted therapies for the treatment of newly diagnosed AML. Expert opinion AZA is a cornerstone for the treatment of patients considered ineligible for intensive chemotherapy induction, but better results and therapies are required for these patients. AZA has shown synergistic properties when combined with other medications. Its safety profile and few drug interactions make it a suitable medication to use as backbone. Newer therapies are being combined with AZA, demonstrating safety and in cases, improved responses, and survival. AZA/venetoclax has emerged as the standard of care for patients who are ineligible for intensive chemotherapy. Doublet and triplet combinations are increasingly being studied. With the results observed in elderly patients, the intensive chemotherapy paradigm might be put to test in younger populations, with AZA combinations being at the forefront.

Neurocognitive deficits in survivors of childhood acute myeloid leukemia

BackgroundAlthough treatment of acute myeloid leukemia (AML) contains neurotoxic agents, studies investigating neurocognitive outcomes in children with AML are sparse. We evaluated late cognitive effects in children treated with a high-dose cytarabine based regimen, focusing on general intellectual ability and specific neurocognitive domains.MethodsWe evaluated 12 survivors of childhood AML who were treated between 2006 and 2016 and completed the Wechsler Intelligence Scales. One-sample t-tests were used to compare full-scale intelligence quotient (FSIQ) and primary index scores to norms. The overall effect of index scores and subtests was examined with one-way ANOVA. Univariate analyses and multiple regression models examined demographic and clinical characteristics associated with FSIQ.ResultsParticipants who underwent the Wechsler Intelligence Scale for Children demonstrated impairment on working memory index and participants who underwent the Wechsler Adult Intelligence Scale showed low score in the subtests that reflect working memory, whereas they exhibited no statistical differences versus the population means for FSIQ. There were no significant differences in the overall effect of index scores and subtests. On univariate analysis, FSIQ were related to time since diagnosis and age at assessment, and both were significant predictors of FSIQ on multiple linear regression.ConclusionsSurvivors of childhood AML exhibited impairment of working memory, even if their FSIQ was within the normal range. Difficulties in specific cognitive domains are associated with reduced quality of life. It is important to identify survivors who are at risk and provide tailored interventions.

Targeting the translational machinery in gastrointestinal stromal tumors (GIST): a new therapeutic vulnerability

Although KIT-mutant GISTs can be effectively treated with tyrosine kinase inhibitors (TKIs), many patients develop resistance to imatinib mesylate (IM) as well as the FDA-approved later-line agents sunitinib, regorafenib and ripretinib. Resistance mechanisms mainly involve secondary mutations in the KIT receptor tyrosine kinase gene indicating continued dependency on the KIT signaling pathway. The fact that the type of secondary mutation confers either sensitivity or resistance towards TKIs and the notion that secondary mutations exhibit intra- and intertumoral heterogeneity complicates the optimal choice of treatment in the imatinib-resistant setting. Therefore, new strategies that target KIT independently of its underlying mutations are urgently needed. Homoharringtonine (HHT) is a first-in-class inhibitor of protein biosynthesis and is FDA-approved for the treatment of chronic myeloid leukemia (CML) that is resistant to at least two TKIs. HHT has also shown activity in KIT-mutant mastocytosis models, which are intrinsically resistant to imatinib and most other TKIs. We hypothesized that HHT could be effective in GIST through downregulation of KIT expression and subsequent decrease of KIT activation and downstream signaling. Testing several GIST cell line models, HHT led to a significant reduction in nascent protein synthesis and was highly effective in the nanomolar range in IM-sensitive and IM-resistant GIST cell lines. HHT treatment resulted in a rapid and complete abolishment of KIT expression and activation, while KIT mRNA levels were minimally affected. The response to HHT involved induction of apoptosis as well as cell cycle arrest. The antitumor activity of HHT was confirmed in a GIST xenograft model. Taken together, inhibition of protein biosynthesis is a promising strategy to overcome TKI resistance in GIST.

Sabatolimab. TIM-3-targeting monoclonal antibody, Treatment of myelodysplastic syndrome, Treatment of acute myeloid leukemia

Sabatolimab. TIM-3-targeting monoclonal antibody, Treatment of myelodysplastic syndrome, Treatment of acute myeloid leukemia

Modulation of energy metabolism to overcome drug resistance in chronic myeloid leukemia cells through induction of autophagy

Tyrosine kinase inhibitors (TKIs) such as imatinib (IM) are key drugs for treatment of chronic myeloid leukemia (CML). Development of drug resistance to TKIs due to BCR-ABL mutation, especially T315I mutation, poses a major challenge in the clinical treatment of CML. The purpose of this study was to test metabolic modulation as a potential strategy to overcome imatinib resistance based on the possible crosstalk between BCR-ABL signaling and metabolic changes in CML. 2-deoxy-d-glucose (2-DG) was used to modulate the glucose metabolism in CML cells sensitive to IM (KBM5 cell line) and resistant to imatinib with BCR-ABL T315I mutation (KBM5-T315I cell line). Seahorse XFe24 extracellular flux analyzer to quantify oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) was used to measure cellular energy metabolism. Cell proliferation was analyzed by CCK-8 assay and MTS assay. Annexin V/PI staining was used to evaluate cell apoptosis. Autophagy-related proteins and enzyme/proteins were detected by Western blotting. Cellular ATP concentration was detected using an ATP-based Cell Titer Kit. The combined action of 2-DG and IM was evaluated by calculating the drug combination index. Our results found that inhibition of glucose metabolism by 2-DG significantly impaired the viability of CML cells and co-treatment with 2-DG and imatinib induced a synergistic inhibition of KBM5 and KBM5-T315I cells. 2-DG induced cell death by autophagy, not by apoptosis, as evidenced by increased expression of Beclin1 and LC3AII and lack of annexin V/PI-positive cells. At the biochemical level, 2-DG inhibited glycolysis and mitochondrial oxygen consumption manifested by a significant decrease in ECAR and OCR, and a depletion of ATP. The severe metabolic stress induced by 2-DG in CML cells led to autophagic cell death. Our results suggested a metabolic vulnerability of CML cells that could be targeted by a combination of 2-DG and imatinib as an alternative treatment for imatinib-resistant CML.