bims-tremyl Biomed News
on Therapy resistance biology in myeloid leukemia
Issue of 2022–10–02
sixty-one papers selected by
Paolo Gallipoli, Barts Cancer Institute, Queen Mary University of London
  1. AML-158 Phase Separation Mediates NUP98 Fusion Oncoprotein Leukemic Transformation.
  2. MDS-431 Outcomes of Transformation to Acute Myeloid Leukemia after Hypomethylating Agent Therapy in Patients With Myelodysplastic Syndromes.
  3. AML-440 Prognosis of Molecularly-Defined Secondary Acute Myeloid Leukemia Patients.
  4. Germline ERCC excision repair 6 like 2 (ERCC6L2) mutations lead to impaired erythropoiesis and reshaping of the bone marrow microenvironment.
  5. AML-432 Overall Survival (OS) by IDH2 Mutant Allele (R140 or R172) in Patients With Late-Stage, Mutant-IDH2 Relapsed/Refractory Acute Myeloid Leukemia (AML) Treated With Enasidenib or Conventional Care Regimens (CCR) in the Randomized, Open-Label, Phase 3 IDHENTIFY Trial.
  6. AML-457 Oral Azacitidine (Oral-AZA) in Patients With Acute Myeloid Leukemia (AML) in First Remission after Intensive Chemotherapy (IC): Long-Term Overall Survival (OS) Results from the Phase 3 QUAZAR AML-001 Trial.
  7. AML-234 Prognostic Value of FLT3-ITD Residual Disease in Acute Myeloid Leukemia.
  8. AML-295 AGILE: A Global, Randomized, Double-Blind, Phase 3 Study of Ivosidenib + Azacitidine Versus Placebo + Azacitidine in Patients With Newly Diagnosed Acute Myeloid Leukemia With an IDH1 Mutation.
  9. Description of a novel subtype of acute myeloid leukemia defined by recurrent CBFB insertions.
  10. AML-279 Molecularly-Defined De Novo and Secondary Acute Myeloid Leukemia Are Biologically and Clinically Different Entities.
  11. AML-262 Pivekimab Sunirine (PVEK, IMGN632) Triplet With Azacitidine and Venetoclax Shows Broad Activity in Adverse Genetic Subsets of Relapsed/Refractory Acute Myeloid Leukemia and Reduced Infusion-Related Reactions.
  12. AML-266 Optimization of a Drug Screening Platform in Acute Myeloid Leukemia.
  13. MDS-508 Contemporary Evaluation of a Cohort of Patients With Clonal Hematopoiesis (CH): A Single Institution Experience.
  14. AML-165 Clinical Outcomes of Patients With FLT3-Mutated Acute Myeloid Leukemia (AML): A Single-Center Retrospective Review.
  15. The genesis and evolution of acute myeloid leukemia stem cells in the microenvironment: From biology to therapeutic targeting.
  16. AML-080 Superior Anti-Leukemic Effects of Combined Acid Ceramidase and Bcl-2 Inhibition in Acute Myeloid Leukemia.
  17. AML-389 Phase 1/2 Study of SEL24/MEN1703, a First-in-Class Dual PIM/FLT3 Kinase Inhibitor, in Patients With IDH1/2-Mutated Acute Myeloid Leukemia: The DIAMOND-01 Trial.
  18. 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.
  19. AML-464 Tolerability and Efficacy of the First-In-Class Anti-CD47 Antibody Magrolimab Combined With Azacitidine in Frontline Patients With TP53-Mutated Acute Myeloid Leukemia (AML): Phase 1b Results.
  20. AML-326 Novel FLT3-ALK2 Dual Inhibitor TP-0184 Inhibits Leukemia Growth by Targeting Serine Biosynthesis in FLT3-ITD-Positive AML Cells.
  21. CML-395 Efficacy and Safety Results From ASCEMBL, a Phase III Study of Asciminib vs. Bosutinib in Patients With Chronic Myeloid Leukemia in Chronic Phase (CML-CP) After ≥2 Prior Tyrosine Kinase Inhibitors (TKIs): Week 96 Update.
  22. AML-131 ERG: From a Fortuitous Discovery to Potential Treatment for AML.
  23. AML-029 Quizartinib Prolonged Overall Survival (OS) vs Placebo Plus Intensive Induction and Consolidation Therapy Followed by Single-Agent Continuation in Patients Aged 18-75 Years With Newly Diagnosed FLT3-Internal Tandem Duplication Positive (FLT3-ITD+) Acute Myeloid Leukemia (AML).
  24. AML-348 A Phase Ib/II Study of Ivosidenib With Venetoclax +/- Azacitidine in IDH1-Mutated Hematologic Malignancies.
  25. AML-342 A Phase II Study of Azacitidine and Venetoclax as Maintenance Therapy in Patients With Acute Myeloid Leukemia.
  26. 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).
  27. AML-055 Outcomes Based on Sequential Use of Venetoclax Based Therapy and Targeted Therapy in Acute Myeloid Leukemia (AML).
  28. AML-488 Impact of Somatic Mutations on Treatment Response and Outcomes in Patients With Core Binding Factor Acute Myeloid Leukemia.
  29. Truncated CSF3 receptors induce pro-inflammatory responses in severe congenital neutropenia.
  30. CML-288 Impact of ASXL1 Mutations on Prognosis of Chronic Phase Chronic Myeloid Leukemia.
  31. HMG20B stabilizes association of LSD1 with GFI1 on chromatin to confer transcription repression and leukemia cell differentiation block.
  32. MDS-416 Myelodysplastic Syndromes in Morocco: Evolution over 15 Years.
  33. AML-250 Mitochondrial Respiration Regulates GPX4 Inhibition-Induced Ferroptosis in Acute Myeloid Leukemia.
  34. AML-256 A Phase 1 Study of Gilteritinib in Combination With Induction and Consolidation Chemotherapy in Patients With Newly Diagnosed Acute Myeloid Leukemia: Final Study Results.
  35. AML-513 The Role of FLT3 Inhibitors in Patients With Acute Myeloid Leukemia (AML) and T(6;9)(P22;Q34).
  36. AML-283 The Genetic Landscape of NUP98-Rearranged Pediatric Leukemia.
  37. 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.
  38. AML-397 Integrated Safety Analysis of Tagraxofusp, a CD123-Directed Targeted Therapy, in Patients With Hematologic Malignancies.
  39. Polyclonal evolution of Fanconi anemia to MDS and AML revealed at single cell resolution.
  40. AML-399 A Phase 2, Open-Label, Multiarm, Multicenter Study to Evaluate Magrolimab Combined With Antileukemia Therapies for First-Line, Relapsed/Refractory, or Maintenance Treatment of Acute Myeloid Leukemia (AML).
  41. The ABNL-MARRO 001 study: a phase 1-2 study of randomly allocated active myeloid target compound combinations in MDS/MPN overlap syndromes.
  42. AML-099 Prolonged XPO1 Inhibition Is Essential for Optimal Anti-Leukemic Activity in NPM1-Mutated AML.
  43. CML-046 Dose Modification Dynamics of Ponatinib in Patients With Chronic-Phase Chronic Myeloid Leukemia From the PACE and OPTIC Trials.
  44. AML-144 Uroporphyrinogen Decarboxylase (UROD) Is a Therapeutically Targetable Dependency in Acute Erythroid Leukemia.
  45. CML-466 Asciminib Provides Durable Molecular Responses in Patients With Chronic Myeloid Leukemia in Chronic Phase (CML-CP) With the T315I Mutation: Updated Efficacy and Safety Data From a Phase I Trial.
  46. Distinct Tumor Necrosis Factor Alpha Receptors Dictate Stem Cell Fitness Versus Lineage Output in Dnmt3a-Mutant Clonal Hematopoiesis.
  47. AML-327 Novel Anti-B7-H3 Blocking Antibody Enhances NK Cell-Mediated Cytotoxicity and Improves Outcomes in AML-Bearing Mice.
  48. CML-047 Post Hoc Analysis of Responses to Ponatinib in Patients With Chronic-Phase Chronic Myeloid Leukemia (CP-CML) by Baseline BCR::ABL1 Level and Baseline Mutation Status in the OPTIC Trial.
  49. AML-108 SELECT-AML-1 Trial in Progress: A Phase 2 Study of Tamibarotene in Combination With Venetoclax and Azacitidine in Previously Untreated Adult Patients Selected for RARA-Positive AML who are Ineligible for Standard Induction Therapy.
  50. ALL-090 Highly Effective Combination of FLT3 and BCL2 Inhibitors in a Preclinical Model of Lineage Ambiguous Leukemia.
  51. AML-328 Phase 2 Study of ASTX727 (Decitabine/Cedazuridine) Plus Venetoclax in Patients With Relapsed/Refractory Acute Myeloid Leukemia or Previously Untreated, Older Adult Patients Unfit for Chemotherapy.
  52. MPN-375 BET Inhibitor Pelabresib (CPI-0610) Combined With Ruxolitinib in Patients With Myelofibrosis - JAK Inhibitor-Naïe or With Suboptimal Response to Ruxolitinib - Preliminary Data From the MANIFEST Study.
  53. Multiparameter analysis of timelapse imaging reveals kinetics of megakaryocytic erythroid progenitor clonal expansion and differentiation.
  54. AML-119 The Impact of Post-Remission Granulocyte Colony-Stimulating Factor (G-CSF) Use (G-CSFu) in the Phase 3 Studies of Venetoclax (Ven) Combination Treatments in Patients (Pts) With Newly Diagnosed Acute Myeloid Leukemia (AML).
  55. The landscape of extrachromosomal circular DNA (eccDNA) in the normal hematopoiesis and leukemia evolution.
  56. AML-147 C-MYC Targeting by Degradation: Novel Dual c-Myc/GSPT1 Degrader GT19715 Exerts Profound Cell Kill In Vitro and In Vivo in Acute Myeloid Leukemia and Lymphomas.
  57. AML-325 Prognostic Impact of RAS and C-KIT Mutations (Single vs. Multiple) in Core-Binding Factor Acute Myeloid Leukemia (CBF-AML) Treated With a Fludarabine, Cytarabine, and G-CSF (FLAG)- Based Regimen.
  58. A machine learning model of response to hypomethylating agents in myelodysplastic syndromes.
  59. AML-251 Overall Survival (OS) With Intensive Chemotherapy (IC) vs Non-IC in Patients With Newly Diagnosed (ND) AML from the Connect® Myeloid Disease Registry Ineligible for Randomized Clinical Trials (RCT).
  60. Inhibition of the CtBP complex and FBXO11 enhances MHC class II expression and anti-cancer immune responses.
  61. RNA-Regulatory Exosome Complex Suppresses an Apoptotic Program to Confer Erythroid Progenitor Cell Survival In Vivo.
  1. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01234-4. [Epub ahead of print]22 Suppl 2 S220
    AML-158 Phase Separation Mediates NUP98 Fusion Oncoprotein Leukemic Transformation.
    Nicole Michmerhuizen, Bappaditya Chandra, Hazheen Shirnekhi, Swarnendu Tripathi, Brittany Pioso, David Baggett, Diana Mitrea, Ilaria Lacobucci, Michael White, Jingjing Chen, Cheon-Gil Park, Huiyun Wu, Stanley Pounds, Anna Medyukhina, Khaled Khairy, Qingsong Gao, Chunxu Qu, Scott Gorman, Simran Bawa, Carolyn Maslanka, Swati Kinger, Priyanka Dogra, Danika Di Giacomo, Cristina Mecucci, Jeffery Klco, Charles Mullighan, Richard Kriwacki.
       CONTEXT: Rearrangements of the nucleoporin 98 gene (NUP98) define a high-risk subset of childhood acute myeloid leukemia (AML). The resulting fusion oncoproteins (FOs) involve the N-terminal, intrinsically disordered region of NUP98, and the C-terminal portion of one of more than 30 identified fusion partners. Approximately one third of fusion partners have DNA-binding homeodomains, and the remaining partners have other domains involved in gene regulation.
    OBJECTIVE: NUP98 FOs have long been known to localize in nuclear puncta. Here, we investigated whether these puncta form by liquid-liquid phase separation (LLPS) and how they might contribute to cell transformation.
    DESIGN: We first focused on the NUP98::HOXA9 (NHA9) FO, in which the HOXA9 fusion partner includes a DNA-binding homeodomain. We expressed GFP-tagged NHA9 in HEK293T cells and characterized the resulting FO-associated nuclear puncta. We also investigated lentiviral FO expression in mouse hematopoietic stem and progenitor cells (HSPCs), studying localization using confocal imaging, self-renewal using colony forming unit assays, and gene expression using RNA sequencing. We next mutated the phenylalanine glycine (FG) repeats of NUP98 to disrupt interactions with other FOs and interacting proteins or mutated the homeodomain of HOXA9 to disrupt DNA binding. Finally, we investigated the applicability of our findings to other NUP98 FOs with and without homeodomains.
    RESULTS: NHA9 localizes in nuclear puncta in HEK293T and HSPCs, and mutation of FG repeats or the HOXA9 homeodomain abrogates puncta formation. Furthermore, expression of NHA9 confers self-renewal, but cell transformation does not occur in FO mutants that fail to form puncta. Upregulation of NUP98 FO target genes, including the HOXA cluster, occurred with expression of NHA9 and transforming, puncta-positive mutants but not in mutant cells that did not form puncta or transform HSPCs. Expression of additional NUP98 FOs (including NUP98::KDM5A, NUP98::LNP1, and NUP98::PRRX1) led to both puncta formation and cell transformation. Finally, cells from a NUP98::KDM5A patient derived xenograft confirmed puncta formation with endogenous FO expression.
    CONCLUSIONS: Taken together, these results demonstrate that NUP98 FOs undergo LLPS, show that phase separation is critical for cell transformation and gene expression changes, and provide rationale to further explore the exploitation of NUP98 FO-associated puncta for therapeutical benefit.
    Keywords:  AML; NUP98; acute myeloid leukemia; fusion oncoprotein; phase separation
    DOI:  https://doi.org/10.1016/S2152-2650(22)01234-4
  2. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01413-6. [Epub ahead of print]22 Suppl 2 S313-S314
    MDS-431 Outcomes of Transformation to Acute Myeloid Leukemia after Hypomethylating Agent Therapy in Patients With Myelodysplastic Syndromes.
    Kunhwa Kim, Faustine Ong, Ziyi Li, Rashmi Kanagal Shamanna, Guillermo Montalban Bravo, Tapan Kadia, Elias Jabbour, Naveen Pemmaraju, Danielle Hammond, Nicholas Short, Farhad Ravandi, Yesid Alvarado, Sherry Pierce, Xiao Qin Dong, Hagop Kantarjian, Guillermo Garcia-Manero, Kelly Chien.
       INTRODUCTION: Most patients with myelodysplastic syndrome (MDS) have progression of disease after hypomethylating agent (HMA) failure, including transformation to acute myeloid leukemia (AML). We aimed to understand the clinical characteristics and outcomes of AML transformation after HMA failure in MDS.
    METHODS: We conducted a retrospective review of 147 patients with newly-diagnosed MDS from 2017-2021 who later developed HMA failure, focusing on AML transformation.
    RESULTS: With a median follow-up time of 19.5 months, 71 patients (48%) developed AML after HMA failure. Patients with eventual transformation were more likely to be younger, have higher bone marrow or peripheral blasts, and lower platelet counts at the time of MDS diagnosis. Moreover, these transformed patients had higher-risk MDS by IPSS-R, more adverse cytogenetics (CG), and more frequent TP53 mutations and less frequent SF3B1 mutations at MDS diagnosis. Patients with AML transformation had a shorter time from diagnosis to HMA failure (7.5 vs. 15.0 months, p<0.001) and overall survival (OS) from HMA failure (4.2 vs. 8.4 months, p=0.003). Age <65 years old, higher-risk IPSS-R, and HMA response was associated with AML transformation by multivariate analysis. In patients with AML transformation, the median overall survival (OS) after AML diagnosis was 4.0 months. After transformation, the median number of treatment lines was 1 with 17% not receiving AML-directed therapy. 52% patients continued HMA-based therapy, and 51% received venetoclax. Out of 44 patients with evaluable responses, 6 achieved complete remission (CR) and 17 attained CR with incomplete hematologic recovery, with an overall response rate of 52%. However, most patients died of refractory disease (73%) and/or complications from pancytopenia (19%). The 60-day and 180-day mortality were high at 33% and 69%, respectively. The type or intensity of treatment was not associated with survival. Therapy-related disease, ELN adverse risk, higher risk CG, and TP53 and KRAS mutations were associated with worse survival. Four of 5 patients who underwent allogeneic stem cell transplantation achieved survival over 1 year (17.7-39.6 months).
    CONCLUSIONS: The outcomes of AML transformation after HMA failure MDS remain extremely poor. Further understanding of the biology and disease characteristics of this patient population is warranted for better treatment approaches.
    Keywords:  AML; MDS; hypomethylating agent; hypomethylating agent failure
    DOI:  https://doi.org/10.1016/S2152-2650(22)01413-6
  3. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01297-6. [Epub ahead of print]22 Suppl 2 S251-S252
    AML-440 Prognosis of Molecularly-Defined Secondary Acute Myeloid Leukemia Patients.
    Rabea Mecklenbrauck, Nora Borchert, Piroska Klement, Carolin Funke, Maximilian Brandes, Louisa-Kristin Dallmann, Walter Fiedler, Jürgen Krauter, Arne Trummer, Bernd Hertenstein, Andreas Voβ, Michael Lübbert, Verena Gaidzik, Konstanze Döhner, Hartmut Döhner, Arnold Ganser, Felicitas Thol, Michael Heuser.
       INTRODUCTION: Mutations in ASXL1, BCOR, EZH2, SF3B1, SRSF2, STAG2, U2AF1 and ZRSR2 were proposed as secondary AML (sAML) defining mutations independent from the patients' history. We evaluated the prognostic impact of molecularly-defined sAML (msAML) patients in the context of the European LeukemiaNet (ELN) risk categories.
    METHODS: 459 adult newly-diagnosed AML patients (median age 54) with available genetic and follow-up data were included. Patients received standard induction and consolidation chemotherapy or underwent allogeneic hematopoietic cell transplantation (alloHCT). Patients were classified as de-novo AML (dnAML), msAML carrying ≥ 1 sAML-defining mutations, and clinically-defined secondary AML (csAML) based on previous medical history and cytogenetics.
    RESULTS: 208 (45%) patients had dnAML, 155 (34%) msAML, and 96 (21%) csAML. 62 msAML patients overlapped with csAML. Of msAML patients, 104 (67%) had 1, 39 (25%) 2, and 12 (8%) 3 or more msAML-defining mutations. The most frequently mutated msAML-defining genes were ASXL1 (n=48, 31%) and SRSF2 (n=44, 28%). The likelihood to reach complete remission (CR) was higher for dnAML compared to msAML patients (92% vs 79%, P =.003), but there was no difference between csAML and msAML patients. The median follow-up of all patients was 5.56 years. The transplantation rate in first CR was similar in dnAML, msAML and csAML patients (33%, 37%, 44%, respectively). Overall survival (OS) was significantly worse in msAML compared to dnAML patients (median OS 3.3 years vs not reached, HR = 1.7, 95%CI 1.2-2.2, P<.001), also when ASXL1 mutated patients were excluded (HR = 1.7, 95%CI 1.2-2.4, P<.001). OS was similar in csAML vs dnAML and in msAML vs csAML patients. In the ELN favorable and intermediate risk groups msAML patients (n=19 and n=52) had a significantly worse OS compared to dnAML patients (n=66 and n=80) (HR=3.1 95%CI 1.5-6.3, P=.001 and HR=2, 95%CI 1.2-3.2, P=.008, respectively). OS was similar in the ELN adverse risk group between msAML (n=79) and dnAML patients (n=31). Accordingly, the ELN risk groups did not stratify OS in msAML patients.
    CONCLUSIONS: msAML-defining mutations identify a subgroup of dnAML patients with poor prognosis and reclassify 10% of all patients in our cohort from favorable/intermediate to the adverse risk group.
    Keywords:  AML; ELN classification; molecular genetics
    DOI:  https://doi.org/10.1016/S2152-2650(22)01297-6
  4. Br J Haematol. 2022 Sep 26.
    Germline ERCC excision repair 6 like 2 (ERCC6L2) mutations lead to impaired erythropoiesis and reshaping of the bone marrow microenvironment.
    Hannah Armes, Findlay Bewicke-Copley, Ana Rio-Machin, Doriana Di Bella, Céline Philippe, Anna Wozniak, Hemanth Tummala, Jun Wang, Teresa Ezponda, Felipe Prosper, Inderjeet Dokal, Tom Vulliamy, Outi Kilpivaara, Ulla Wartiovaara-Kautto, Jude Fitzgibbon, Kevin Rouault-Pierre.
      Despite the inclusion of inherited myeloid malignancies as a separate entity in the World Health Organization Classification, many established predisposing loci continue to lack functional characterization. While germline mutations in the DNA repair factor ERCC excision repair 6 like 2 (ERCC6L2) give rise to bone marrow failure and acute myeloid leukaemia, their consequences on normal haematopoiesis remain unclear. To functionally characterise the dual impact of germline ERCC6L2 loss on human primary haematopoietic stem/progenitor cells (HSPCs) and mesenchymal stromal cells (MSCs), we challenged ERCC6L2-silenced and patient-derived cells ex vivo. Here, we show for the first time that ERCC6L2-deficiency in HSPCs significantly impedes their clonogenic potential and leads to delayed erythroid differentiation. This observation was confirmed by CIBERSORTx RNA-sequencing deconvolution performed on ERCC6L2-silenced erythroid-committed cells, which demonstrated higher proportions of polychromatic erythroblasts and reduced orthochromatic erythroblasts versus controls. In parallel, we demonstrate that the consequences of ERCC6L2-deficiency are not limited to HSPCs, as we observe a striking phenotype in patient-derived and ERCC6L2-silenced MSCs, which exhibit enhanced osteogenesis and suppressed adipogenesis. Altogether, our study introduces a valuable surrogate model to study the impact of inherited myeloid mutations and highlights the importance of accounting for the influence of germline mutations in HSPCs and their microenvironment.
    Keywords:  acute myeloid leukaemia (AML) and myelodysplastic syndrome (MDS); familial leukaemia; haematopoietic stem/progenitor cells; mesenchymal cells; niche and bone marrow microenvironment
    DOI:  https://doi.org/10.1111/bjh.18466
  5. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01293-9. [Epub ahead of print]22 Suppl 2 S249-S250
    AML-432 Overall Survival (OS) by IDH2 Mutant Allele (R140 or R172) in Patients With Late-Stage, Mutant-IDH2 Relapsed/Refractory Acute Myeloid Leukemia (AML) Treated With Enasidenib or Conventional Care Regimens (CCR) in the Randomized, Open-Label, Phase 3 IDHENTIFY Trial.
    Courtney D DiNardo, Stéphane de Botton, Alberto Risueño, Andre C Schuh, Bob Löwenberg, Hee-Je Kim, Paresh Vyas, Andrew H Wei, Eytan M Stein, Hartmut Döhner, Amir T Fathi, Patricia Martin-Regueira, Lilia Taningco, Iryna Bluemmert, Xin Yu, Wendy L See, Maroof Hasan.
       CONTEXT: IDH2 mutations (mIDH2) occur in ~8%-19% of patients with AML, typically as R140Q (~75%) or R172K (~25%) point mutations, which have distinct functional effects and prognostic relevance. In the phase 3 IDHENTIFY trial, enasidenib did not significantly improve OS vs CCR in older patients with mIDH2 relapsed/refractory AML, but a trend for improved OS with enasidenib was detected in patients with IDH2-R172.
    OBJECTIVE: Investigate molecular profiles and OS in mIDH2 variant subgroups (R140/R172).
    METHODS: IDHENTIFY (NCT02577406) enrolled patients aged ≥60 years who had received 2-3 prior AML-directed therapies. Patients were randomized 1:1 to enasidenib 100-mg/day or CCR (azacitidine, intermediate- or low-dose Ara-C, or supportive care). Co-occurring mutations were identified by targeted NGS of BMMC DNA. Total 2-hydroxyglutarate was determined by LC/MS.
    RESULTS: Of 319 patients enrolled, 88 (28%; 43 enasidenib, 45 CCR) had mIDH2-R172 and 229 (72%; 115 enasidenib, 114 CCR) had mIDH2-R140. Median baseline 2-hydroxyglutarate level and IDH2 VAF were similar between arms and mIDH2 subgroups. Patients with mIDH2-R172 had fewer baseline mutations (median 4 [range 2-8]) than those with mIDH2-R140 (5 [1-11]) (P<0.0001). Common co-mutations were SRSF2 and RUNX1 in the R140 cohort (59% each) and DNMT3A in the R172 cohort (57%). Compared with R172, R140 was enriched with SRSF2, FLT3 (-ITD/-TKD), NPM1, RUNX1, and JAK2, whereas DNMT3A and TP53 were more common with R172. In Cox multivariate analysis including mIDH2 variant, DNMT3A status, and number of baseline mutations, mIDH2-R172 was significantly correlated with improved OS (P=0.04 vs R140) in the enasidenib arm, and number of baseline mutations was significantly (P<0.01) associated with OS in the CCR arm. Median OS in the R172 subgroup was 14.6 months with enasidenib vs 7.8 months with CCR (HR, 0.59 [95%CI 0.35-0.98]; P=0.039); 1-year survival rates were 62% and 30%. In the R140 subgroup, median OS was 5.7 months in both arms (0.93 [0.70-1.24]; P=0.61), and 1-year survival rates were 29% and 25% with enasidenib and CCR.
    CONCLUSIONS: Mutational burden and co-mutational profiles differed between patients with mIDH2-R140 and mIDH2-R172 relapsed/refractory AML. In the R172 subgroup, median OS and 1-year survival rate with enasidenib were approximately double those with CCR.
    Keywords:  AML; IDH2, relapsed/refractory; Phase III; biomarkers; enasidenib
    DOI:  https://doi.org/10.1016/S2152-2650(22)01293-9
  6. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01298-8. [Epub ahead of print]22 Suppl 2 S252-S253
    AML-457 Oral Azacitidine (Oral-AZA) in Patients With Acute Myeloid Leukemia (AML) in First Remission after Intensive Chemotherapy (IC): Long-Term Overall Survival (OS) Results from the Phase 3 QUAZAR AML-001 Trial.
    Farhad Ravandi, Andrew H Wei, Hartmut Döhner, Hamid Sayar, Pau Montesinos, Hervé Dombret, Dominik Selleslag, Kimmo Porkka, Jun Ho Jang, Barry Skikne, C L Beach, Yu Olivia Tian, Gail J Roboz.
       CONTEXT: In the QUAZAR AML-001 trial, Oral-AZA significantly prolonged OS vs placebo (median 24.7 vs 14.8 months; P<0.001) in patients with AML in remission after IC and ineligible for transplant. At the primary data cutoff (July 2019) Kaplan-Meier (KM) OS curves for Oral-AZA and placebo converged after ~48 months; 26.5% of patients remained alive and the trial was unblinded.
    OBJECTIVE: Assess OS at an updated cutoff with additional follow-up.
    METHODS: Patients ≥55 years of age, with intermediate- or poor-risk cytogenetics at diagnosis and ECOG PS ≤3, were randomized to Oral-AZA 300mg or placebo once-daily for 14 days/28-day cycle within 4 months of first CR/CRi. After unblinding, Oral-AZA-treated patients could continue treatment in an extension phase. OS was the time from randomization to death, consent withdrawal, or loss to follow-up. Baseline characteristics were compared for long-term (LT) survivors (alive ≥3 years from randomization) versus non-LT survivors.
    RESULTS: 472 patients were randomized to Oral-AZA (n=238) or placebo (n=234); 39 (16%) Oral-AZA patients entered the extension phase. At the updated data cutoff (Sep 2020), 54 (23%) Oral-AZA patients and 35 (15%) placebo patients were alive; 31 (13%) patients were still receiving Oral-AZA. At a median follow-up of 51.7 months, median OS was unchanged from the primary cutoff (24.7 vs 14.8 months; P=0.0008). However, KM curves showed greater separation at later time-points and did not overlap. KM-estimated 3-year OS rate was 37.4% with Oral-AZA versus 27.9% with placebo (Δ+9.5% [95% CI, 0.9-18.1]). Compared with non-LT survivors, LT survivors (n=140; 83 Oral-AZA, 57 placebo) were more likely to have intermediate-risk cytogenetics (95% vs 82%, respectively) and NPM1mut (45% vs 23%) at AML diagnosis, and less likely to have measurable residual disease (MRD) post-IC (33% vs 52%). Among baseline MRD+ patients, 71% (34/48) of LT survivors became MRD- on study, versus 15% (26/172) of non-LT survivors (P<0.0001).
    CONCLUSIONS: At LT follow-up, median OS was unchanged, but at later time-points the tails of the Oral-AZA and placebo OS curves showed greater separation, indicating sustained LT OS benefit with Oral-AZA. Intermediate-risk cytogenetics and NPM1mut at diagnosis, and absence of post-IC MRD, were associated with LT survival.
    Keywords:  AML; Phase III; azacitidine; maintenance
    DOI:  https://doi.org/10.1016/S2152-2650(22)01298-8
  7. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01249-6. [Epub ahead of print]22 Suppl 2 S227
    AML-234 Prognostic Value of FLT3-ITD Residual Disease in Acute Myeloid Leukemia.
    Christian Vonk, Tim Grob, Mathijs Sanders, François Kavelaars, Melissa Rijken, Diana Hanekamp, Patrycja Gradowska, Jaqueline Cloos, Yngvar Fl Isand, Marinus van Marwijk Kooy, Markus Manz, Gert Ossenkoppele, Lidwine Tick, Marie-Christiane Vekemans, Bob Löwenberg, Mojca Jongen-Lavrencic, Peter Valk.
       CONTEXT: FLT3-internal tandem duplications (FLT3-ITD) are among the most common genetic molecular abnormalities in acute myeloid leukemia (AML) patients. Here, the prognostic impact of the presence of minimal residual disease (MRD) of FLT3-ITD in AML patients is assessed by next-generation sequencing (NGS).
    OBJECTIVE: The prognostic significance of FLT3-ITD in AML in relation to other concurrent gene mutations and allelic mutational burden has remained a subject of scientific controversy. Detection of FLT3-ITD MRD by RQ-PCR is restricted by patient-specific variables, such as sequence, position, and length. However, systematic studies analyzing the applicability of FLT3-ITD MRD detection with NGS techniques are currently lacking. Here, we evaluate the impact of the presence of FLT3-ITD MRD detected by NGS on treatment outcome in the context of current prognostic factors at diagnosis and MRD status measured by multiparameter flow cytometry (MFC) and mutant NPM1.
    METHODS: In 161 de novo AML patients with an FLT3-ITD enrolled in the HOVON-SAKK clinical trials, NGS was performed at diagnosis and ultra-deep in CR after induction chemotherapy. Presence of FLT3-ITD MRD was correlated to incidence of relapse and overall survival (OS).
    RESULTS: NGS-based FLT3-ITD MRD was present in 47 of 161 (29%) AML patients. Presence of FLT3-ITD MRD was associated with increased risk of relapse (4-year CIR, 75% FLT3-ITD MRD vs. 33% no FLT3-ITD MRD; P<0.001) and inferior OS (4-year OS, 31% FLT3-ITD MRD vs. 57% no FLT3-ITD MRD; P<0.001). In multivariate analysis, detection of FLT3-ITD MRD in CR confers independent prognostic significance for relapse (hazard ratio, 3.55; P<0.001) and OS (hazard ratio 2.51; P<0.001). Presence of FLT3-ITD MRD exceeds the prognostic value of most of the generally accepted clinical and molecular prognostic factors, including the FLT3-ITD allelic ratio at diagnosis and MRD status of mutant NPM1 and MFC.
    CONCLUSIONS: Presence of FLT3-ITD MRD in CR detected by NGS after induction chemotherapy identifies AML patients with an increased risk of relapse and inferior OS that outweighs the significance of currently accepted prognostic factors. This finding offers support for the use of FLT3-ITD MRD as a clinically relevant biomarker for dynamic disease risk assessment in AML.
    Keywords:  AML; FLT3-ITD; MRD; acute myeloid leukemia; minimal residual disease; next generation sequencing
    DOI:  https://doi.org/10.1016/S2152-2650(22)01249-6
  8. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01262-9. [Epub ahead of print]22 Suppl 2 S234
    AML-295 AGILE: A Global, Randomized, Double-Blind, Phase 3 Study of Ivosidenib + Azacitidine Versus Placebo + Azacitidine in Patients With Newly Diagnosed Acute Myeloid Leukemia With an IDH1 Mutation.
    Hartmut Dohner, Pau Montesinos, Susana Vives Polo, Ewa Zarzycka, Jianxiang Wang, Giambattista Bertani, Michael Heuser, Rodrigo T Calado, Andre C Schuh, Su-Peng Yeh, Adolfo de la Fuente, Claudio Cerchione, Scott R Daigle, Jianan Hui, Shuchi S Pandya, Diego A Gianolio, Christian Recher, Stephane de Botton.
       CONTEXT: Isocitrate dehydrogenase 1 (IDH1) mutations are oncogenic drivers in acute myeloid leukemia (AML), with 6-10% of AML patients harboring mutant IDH1 (mIDH1). Ivosidenib (IVO) is a small molecule mIDH1 inhibitor that silences the oncogenic pathways activated by this mutation.
    OBJECTIVE: Assess efficacy/safety of IVO+azacitidine (AZA) as frontline therapy for AML patients ineligible for intensive chemotherapy (IC).
    DESIGN: Randomized, placebo (PBO)-controlled, global phase 3 study.
    PATIENTS: Patients with untreated AML, centrally confirmed mIDH1 status, ineligible for IC.
    INTERVENTIONS: Once daily IVO 500 mg (or PBO) plus AZA 75 mg/m2 for 7 days in 28-day cycles.
    MAIN OUTCOME MEASURES: Event-free survival (EFS), overall survival (OS), response rates, blood counts, transfusion dependence, health-related quality of life (HRQoL), and adverse events (AEs).
    RESULTS: 146 patients were randomized to IVO+AZA (n=72) and PBO+AZA (n=74). Median age was 76.0 and 75.5 years, respectively. EFS was significantly in favor of IVO+AZA (HR=0.33; 1-sided P=0.0011). Median OS was 24.0 vs 7.9 months for IVO+AZA vs PBO+AZA, respectively (HR=0.44; 1-sided P=0.0005). Complete response rates were 47.2% and 14.9% for IVO+AZA vs PBO+AZA, respectively (P<0.0001). During 2 weeks after treatment initiation, only the IVO+AZA treatment group showed an increase in absolute neutrophil count (from 0.99×109/L at baseline to 2.05×109/L at week 2). Significantly more patients in the IVO+AZA group became RBC and platelet transfusion independent (2-sided P=0.006). IVO+AZA preserved or improved HRQoL from treatment cycles 5 to 19, with few clinically meaningful improvements with PBO+AZA. Grade ≥3 AEs occurring in >20% of patients receiving IVO+AZA vs PBO+AZA included febrile neutropenia (28.2% vs 34.2%), anemia (25.4% vs 26.0%), thrombocytopenia (23.9% vs 20.5%), pneumonia (22.5% vs 28.8%), and infections (21.1% vs 30.1%).
    CONCLUSIONS: In patients with IC-ineligible, newly diagnosed mIDH1 AML, IVO+AZA significantly improved EFS, OS, and clinical response compared with PBO+AZA. Blood counts rapidly recovered in patients given IVO+AZA, patients were less dependent on RBC/platelet transfusion than those given PBO+AZA, with HRQoL improvements in the IVO+AZA group. The safety profile of IVO+AZA was favorable, with fewer febrile neutropenia and infection events with IVO+AZA vs PBO+AZA.
    Keywords:  AML; acute myeloid leukemia; ivosidenib; mutations in isocitrate dehydrogenase 1
    DOI:  https://doi.org/10.1016/S2152-2650(22)01262-9
  9. Blood. 2022 Sep 30. pii: blood.2022017874. [Epub ahead of print]
    Description of a novel subtype of acute myeloid leukemia defined by recurrent CBFB insertions.
    Georgina Ryland, Masayuki Umeda, Linda Holmfeldt, Sören Lehmann, Morten Krogh Herlin, Jing J Ma, Mahsa Khanlari, Jeffrey E Rubnitz, Rhonda E Ries, Hansen J Kosasih, Paul G Ekert, Hwee Ngee Goh, Ing Soo Tiong, Sean M Grimmond, Claudia Haferlach, Ryan B Day, Timothy J Ley, Soheil Meshinchi, Xiaotu Ma, Piers Blombery, Jeffery M Klco.
      
    DOI:  https://doi.org/10.1182/blood.2022017874
  10. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01259-9. [Epub ahead of print]22 Suppl 2 S232
    AML-279 Molecularly-Defined De Novo and Secondary Acute Myeloid Leukemia Are Biologically and Clinically Different Entities.
    Emma Boertjes, Adil Al Hinai, Elodie Stoetman, Kyra G Compagne, Tim Grob, Francois G Kavelaars, Melissa Rijken, Mathijs Sanders, Berna H Beverloo, Bob Löwenberg, Peter J M Valk.
       CONTEXT: Acute myeloid leukemia (AML) is a heterogeneous disease, which can be clinically classified in de novo AML or secondary AML (sAML) and separate from therapy-related AML. Secondary AML evolves from an antecedent hematological disorder, whereas de novo AML arises in absence of any prior hematological disease or leukemogenic treatment. A broad range of genetic and cytogenetic abnormalities that directly contribute to the development of AML has been identified. Nevertheless, the association of these markers with leukemia ontogeny and clinical response is not completely understood.
    OBJECTIVE: The primary aim of this study was to discriminate de novo AML from secondary type AML (stAML) based on the occurrence of molecular and cytogenetic markers in a unique large cohort of AML patients (n=2,447) enrolled in the Dutch-Belgian Cooperative Trial Group for Hematology-Oncology (HOVON) or the Swiss Group for Clinical Cancer Research (SAKK) clinical trials. All patients received intensive treatment. We investigated the clinical and biological differences between de novo AML and sAML with the underlying hypothesis that (molecularly defined) de novo AML and stAML should be considered as two different entities.
    RESULTS: In our unique AML cohort, we demonstrated that RUNX1, EZH2, SRSF2, STAG2, ZRSR2, SF3B1, ASXL1 and U2AF1 significantly associated with clinically proven sAML (p<0.01). AML cases carrying these mutations were referred to as stAML. Mutations in NPM1, CEBPA (bi-allelic), FLT3-ITD, inv(16), t(8;21) and aberrations involving 11q23 were included as class-defining for de novo AML. AML patients with TP53 mutations were removed from all analyses since this genetically and clinically distinct subtype of AML should be considered as a separate entity. In comparison to de novo AML (n=1705), patients with stAML (n=742) were older (p<0.01), were more likely to be male (p<0.01), carried a higher number of driver mutations (p<0.01), had lower white blood cell counts (p<0.01), more frequently lower bone marrow blast and blood neutrophil counts (p<0.01). Importantly, patients with stAML had a significant inferior event-free (p<0.001) and overall survival (p<0.001).
    CONCLUSIONS: In conclusion, we revealed molecularly defined stAML as an AML subtype with a distinct genetic ontogeny that emphasizes a subgroup of patients with significantly worse clinical outcomes.
    Keywords:  AML; acute myeloid leukemia; genetics; neoplasm
    DOI:  https://doi.org/10.1016/S2152-2650(22)01259-9
  11. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01257-5. [Epub ahead of print]22 Suppl 2 S231-S232
    AML-262 Pivekimab Sunirine (PVEK, IMGN632) Triplet With Azacitidine and Venetoclax Shows Broad Activity in Adverse Genetic Subsets of Relapsed/Refractory Acute Myeloid Leukemia and Reduced Infusion-Related Reactions.
    Naval Daver, Pau Montesinos, Ahmed Aribi, Giovanni Martinelli, Jessica K Altman, Eunice S Wang, Gail J Roboz, Patrick W Burke, Gianluca Gaidano, Roland B Walter, Xavier Thomas, Deepa Jeyakumar, Daniel J DeAngelo, Harry P Erba, Elisabetta Todisco, Kebede Begna, Anjali Advani, Lauris Gastaud, Adolfo de la Fuente, Antonio Curti, Lourdes M Mendez, Paresh Vyas, Nicolas Boissel, Norbert Vey, Christian Recher, Thomas Longval, Uwe Platzbecker, Silke Kapp-Schwörer, Christoph Schliemann, Marina Konopleva, Laura Torres, David A Sallman, Guido Marcucci, Giovanni Marconi, Hagop Kantarjian, Callum M Sloss, Karen E Malcolm, Patrick A Zweidler-McKay, Kendra Sweet.
       CONTEXT: Pivekimab sunirine (PVEK, IMGN632) is a first-in-class ADC comprising a CD123 high-affinity antibody, a cleavable linker, and an IGN (indolinobenzodiazepine pseudodimer) payload. PVEK with azacitidine (AZA) and venetoclax (VEN) is a novel triplet that has demonstrated anti-leukemia activity in relapsed/refractory AML patients.
    OBJECTIVE: Evaluate the anti-leukemia activity in genetic subgroups of AML and safety of the triplet.
    INTERVENTION: Patients with relapsed/refractory AML received PVEK+AZA+VEN in a three-drug escalation over a 28-day cycle: PVEK 0.015 or 0.045 mg/kg day 7, AZA 50 or 75 mg/m2 days 1-7, and VEN 400 mg for 8, 14, or 21 days.
    RESULTS: Twenty-nine patients (median age 67 y, ELN adverse 62%, prior VEN 48%) were in higher-intensity cohorts (PVEK 0.045 mg/kg and/or VEN for 14 or 21 days). The overall response rate (ORR) was 59% (4 CR, 6 CRh, 1 CRp, 6 MLFS) and the composite complete remission rate (CCR, CR+CRh+CRp+CRi) was 38%. Higher rates are seen in patients with FLT3-ITD (n=9, ORR 89%, CCR 78%), IDH2 (n=4, ORR 75%, CCR 75%), and WT1 (n=7, ORR 57%, CCR 43%) mutations. Lower rates are seen in patients with monosomy 7/abn7q (n=6, ORR 17%, CCR 17%), TP53 (n=4, ORR 25%, CCR 25%), and ASXL1 (n=6, ORR 67%, CCR 17%) deletions or mutations. The safety profile for the PVEK triplet is similar to AZA+VEN. No VOD, TLS, or CRS was reported. IRRs were reported in 33% (n=17, one grade 4) of patients given 1 dose of dexamethasone (8 mg) as premedication (n=51); these IRRs were most frequently tachycardia and chills, with no anaphylactic reactions reported. Following the data cut-off, there was a second grade 4 IRR, and the prophylactic regimen was increased with two additional doses of dexamethasone on the day prior to the PVEK dose. The IRR rate has dropped to 8% (3 of 38), with no grade 3+; all were grades 1-2 that resolved with limited intervention (P<0.01).
    CONCLUSIONS: The PVEK triplet with AZA+VEN demonstrates anti-leukemic activity across multiple high-risk genetic subsets of relapsed/refractory AML. Prophylactic steroids added on day -1 have significantly reduced IRRs. Expansion cohorts are now enrolling for untreated and relapsed AML patients (NCT04086264).
    Keywords:  ADC; AML; combination therapy; pivekimab
    DOI:  https://doi.org/10.1016/S2152-2650(22)01257-5
  12. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01258-7. [Epub ahead of print]22 Suppl 2 S232
    AML-266 Optimization of a Drug Screening Platform in Acute Myeloid Leukemia.
    Laureen Chat, Justine Pasanisi, Kim Pacchiardi, Alya Pioton, Matthieu Duchmann, Raphaël Itzykson.
       CONTEXT: Acute myeloid leukemia (AML) is a group of hematological diseases with a poor prognosis. Functional ex-vivo drug screening of primary AML cells could identify patient-specific vulnerabilities and improve the treatment of AML patients. To determine the chemosensitivity of primary cells from AML patients, we previously developed a multiparametric niche-like drug screening platform (NEXT platform, Reinaldo Dal Bello, ASH, 2020).
    OBJECTIVE: Optimization of an ex-vivo niche-like drug screening platform on primary AML samples to prospectively recommend second-line treatment for AML patients.
    SETTINGS: Primary cells from 49 consecutive patients with newly diagnosed AML were cultured for 72 hours in niche-like conditions (conditioned media, mesenchymal stroma, hypoxia) and exposed to 36 molecules at 8 concentrations. Subsequently, total leukemic cells, blasts, lymphocytes, differentiated cells, and leukemic stem cell counts were assessed using multiparametric high-throughput flow cytometry (iQue3 Intellycyt). Drug activity was assessed using a drug sensitivity score (DSS, Yadov et al., Scientific Reports, 2014) after normalization to DMSO controls. A drug was considered inactive (DSS=0), moderately effective (0<DSS<50), or very effective (DSS≥50).
    RESULTS: We validated the use of frozen cells that provided a similar number of live cells (3492±2808, n=32) as fresh samples (2,398±2,567, n=5, P=0.29). We upscaled the assay to a 384-well plate to increase the number of tested drugs, with a minimum of 7.5 million cells required for testing the 36 drugs. Across the 49 patients, the median number of drugs with strong or moderate activity was 4 (range 0 to 13). In 42 (86%) patients, at least one drug had moderate activity and 22 (49%) had strong activity. We identified 6 top drugs that are moderately effective or very effective in more than 40% of patients: selinexor, ponatinib, palbociclib, sunitinib, and S63845.
    CONCLUSIONS: During this study, we validated and upscaled our NEXT platform on 49 patients. The prospective application of our niche-like drug screening platform is now being investigated in relapsed/refractory AML patients accrued to the multicenter study ALFA-PPP (NCT04777916).
    Keywords:  AML; acute myeloid leukemia; drug screening; precision medicine
    DOI:  https://doi.org/10.1016/S2152-2650(22)01258-7
  13. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01424-0. [Epub ahead of print]22 Suppl 2 S319
    MDS-508 Contemporary Evaluation of a Cohort of Patients With Clonal Hematopoiesis (CH): A Single Institution Experience.
    Faustine Ong, Kunhwa Kim, Rashmi Kanagal Shamanna, Courtney DiNardo, Koichi Takahashi, Tapan Kadia, Elias Jabbour, Nicholas J Short, Danielle Hammond, Naveen Pemmaraju, Sherry A Pierce, Guillermo Montalban Bravo, Hagop Kantarjian, Guillermo Garcia-Manero, Kelly S Chien.
       CONTEXT: Therapy-related CH and the effect of concomitant malignancies hasn't been fully characterized.
    DESIGN: We conducted a retrospective review of 78 CH patients from a single tertiary cancer center (2015-2021). Patients were categorized into 4 groups: CH of indeterminate potential (CHIP) on active primary cancer treatment (CHIP/T, n=6), other CHIP (CHIP/N, n=26), clonal cytopenia of undetermined significance (CCUS) on concurrent primary cancer therapy or with active malignancies (CCUS/T, n=13), and other CCUS (CCUS/N, n=26).
    RESULTS: Median age at CH diagnosis was 72 in all patients, whereas median age of CHIP/T was younger at 66. Majority of study patients had another cancer diagnosis (76%) or cardiovascular comorbidities (73%). Most baseline characteristics were comparable, but more CHIP patients had normal cytogenetics. The most common mutations were DNMT3A (40%), TET2 (31%), TP53 (26%), and ASXL1 (18%). Median variant allelic frequency was 7.8%. TP53 mutations were more frequently seen in CCUS. All patients with CHIP were observed, and some CCUS/N (49%) and CCUS/T (31%) received CH-directed therapy, including growth factors, immunoglobulin, cyclosporine, rituximab, and corticosteroids. Twelve patients transformed to myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML) with a median time to transformation of 6.8 months since CH diagnosis. Transformation occurred in 21% CCUS/T, 17% CHIP/T, 15% CCUS/N, and 4% CHIP/N. Median overall survival (OS) after transformation was not reached, with a 2-year OS of 64%. CCUS/T had inferior survival with median OS of 32 months, whereas median OS of all 3 other groups was not reached. There were no significant differences in OS by transformation status, comorbidities, TP53 mutations, or previous treatment history. The most common causes of death were primary malignancy (35%) and comorbidities or transformation to MDS/AML (20% each).
    CONCLUSIONS: This is a tertiary cancer center CH experience with 76% having another malignancy. Median time to transformation to MDS/AML was short at 6.8 months, but patients had a favorable outcome with 2-year OS at 64% and only 20% CH-related deaths. CCUS/T had a higher rate of transformation to myeloid neoplasms at 21% with inferior survival, warranting possible therapeutic interventions in these high-risk patients in the future.
    Keywords:  MDS; acute myeloid leukemia; clonal hematopoiesis; myelodysplastic syndrome
    DOI:  https://doi.org/10.1016/S2152-2650(22)01424-0
  14. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01236-8. [Epub ahead of print]22 Suppl 2 S221
    AML-165 Clinical Outcomes of Patients With FLT3-Mutated Acute Myeloid Leukemia (AML): A Single-Center Retrospective Review.
    Binoy Yohannan, Frances Cervoni-Curet, Arthi Sridhar, Wei Yang, Adan Rios.
       CONTEXT: Fms-like tyrosine kinase-3 (FLT3) gene activating mutations predominate in AML, with internal tandem duplication (ITD) in 25 to 35% and point mutations in 5 to 7% of patients with normal karyotype. They associate with shorter relapse-free survival (RFS) and inferior outcome.
    OBJECTIVE: To examine targeted FLT-3 mutations therapy during induction chemotherapy (IC) of AML.
    DESIGN: We reviewed all FLT3 mutated AML (both ITD and point mutations in the tyrosine kinase domain (TKD)) patients treated with FLT-3 targeted therapy during IC from March 2013 till December 2021.
    PATIENTS OR OTHER PARTICIPANTS: 28 patients (de novo AML=22, APL=6) with FLT3 mutated AML were identified.
    INTERVENTIONS: Fit patients received IC with fludarabine, cytarabine, and idarubicin (FIA) or IA (3+7 regimen). Older patients received hypomethylating agents (HMA) alone or with venetoclax (Ven). All received IC with FLT3 inhibitors (FLT3I, gilteritinib). All 6 APL patients achieved CR with arsenic trioxide (ATO) and all-trans-retinoic acid (ATRA).
    MAIN OUTCOME MEASURES: Analysis included overall response rate (ORR), complete response (CR), and relapse-free survival (RFS).
    RESULTS: 14 patients (50%) were men. Races included Whites (n=9), Blacks (n=6), Hispanics (n=8) and Others (n=5). The median age was 54 years (range, 20-68). 20 (71.40%) had ITD mutation, 4 (14.20%) had TKD mutation and 4 had both. 15 had NPM1 and 3 DNMT3A mutations. 14 patients had intermediate and 8 adverse risk AML (ELN). Of the AML patients 14 received standard, IC (FIA=8, IA=2, FIA+FLT3I=4), and 12 (85%) achieved CR. Unfit patients received (HMA alone=2, HMA+ Ven=4, HMA+Ven+FLT3I=1, HMA+FLT3I=1). The ORR was 60% with 50% CR. One FIA dead during IC. Three AML patients (10.70%) had allogeneic stem cell transplantations (ASCTs) and had remained in CR. Two non-ASCT were treated with HMA and one with FLT3I maintenance remaining in CR. 4 patients (14.20%) died in remission. Median relapse-free survival (RFS) was 360 days (range, 218-669). The median RFS for non-ASCT patients was 240 days (range, 195-405).
    CONCLUSIONS: Historically RFS in FLT-3 AML is 120 days. IC with FLT3I is highly effective with low induction mortality. Response duration was shorter in the non-ASCT group. In FLT-3 AML ASCT ineligible patients, maintenance therapy may reduce relapse risk.
    Keywords:  AML; AML-FLT3; FLT-3 mutations; gilteritinib; relapse-free survival; targeted therapy
    DOI:  https://doi.org/10.1016/S2152-2650(22)01236-8
  15. Cell Death Discov. 2022 Sep 26. 8(1): 397
    The genesis and evolution of acute myeloid leukemia stem cells in the microenvironment: From biology to therapeutic targeting.
    Yongfeng Chen, Jing Li, Linglong Xu, Mihnea-Alexandru Găman, Zhenyou Zou.
      Acute myeloid leukemia (AML) is a hematological malignancy characterized by cytogenetic and genomic alterations. Up to now, combination chemotherapy remains the standard treatment for leukemia. However, many individuals diagnosed with AML develop chemotherapeutic resistance and relapse. Recently, it has been pointed out that leukemic stem cells (LSCs) are the fundamental cause of drug resistance and AML relapse. LSCs only account for a small subpopulation of all leukemic cells, but possess stem cell properties, including a self-renewal capacity and a multi-directional differentiation potential. LSCs reside in a mostly quiescent state and are insensitive to chemotherapeutic agents. When LSCs reside in a bone marrow microenvironment (BMM) favorable to their survival, they engage into a steady, continuous clonal evolution to better adapt to the action of chemotherapy. Most chemotherapeutic drugs can only eliminate LSC-derived clones, reducing the number of leukemic cells in the BM to a normal range in order to achieve complete remission (CR). LSCs hidden in the BM niche can hardly be targeted or eradicated, leading to drug resistance and AML relapse. Understanding the relationship between LSCs, the BMM, and the generation and evolution laws of LSCs can facilitate the development of effective therapeutic targets and increase the efficiency of LSCs elimination in AML.
    DOI:  https://doi.org/10.1038/s41420-022-01193-0
  16. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01218-6. [Epub ahead of print]22 Suppl 2 S211-S212
    AML-080 Superior Anti-Leukemic Effects of Combined Acid Ceramidase and Bcl-2 Inhibition in Acute Myeloid Leukemia.
    Johnson Ung, Su-Fern Tan, Jeremy Shaw, Todd Fox, Mark Kester, David Feith, Thomas Loughran.
       CONTEXT: Acute myeloid leukemia (AML) is an aggressive, heterogenous disease characterized by clonal expansion of immature myeloid blasts. For the last five decades, intensive induction chemotherapy was the primary treatment option for AML. The 5-year survival rate for younger patients following induction chemotherapy is 40%-50%, which is far superior to the dismal 10%-15% 5-year survival seen in older adult patients, who constitute most AML cases. The specific Bcl-2 antagonist venetoclax was approved in combination with Ara-C or azacitidine for newly diagnosed AML or older adult patients unable to tolerate intensive chemotherapy. However, responses are incomplete and relapse rates remain high, necessitating the development of novel treatment strategies to augment current therapies and improve outcomes. To this end, targeting dysregulated sphingolipid metabolism in AML shows promise. Once overlooked as mere structural membrane components, sphingolipids are now appreciated as important regulators of cell signaling and are involved in many hallmarks of cancer that are of critical importance in AML. Acid ceramidase (AC), a ceramide-catabolizing lipid hydrolase, is upregulated in AML and correlates with poorer patient survival. The breakdown of ceramide, a bona fide pro-death lipid, by AC promotes chemotherapeutic resistance and leukemic survival in part by upregulating Mcl-1, a known venetoclax resistance factor.
    OBJECTIVE: Our ongoing research aims to characterize the efficacy of venetoclax combined with AC inhibition in AML.
    RESULTS: SACLAC, a ceramide analog and irreversible AC inhibitor, augmented venetoclax sensitivity and synergistically decreased cell viability and induced apoptosis in AML cell lines with de novo and acquired venetoclax resistance. Remarkably, combinatorial SACLAC and venetoclax treatment was quantitatively more synergistic than standard venetoclax-containing AML treatment regimens (venetoclax+Ara-C and venetoclax+azacitidine) by Bliss analysis in over 60% of primary patient samples tested in vitro. The SACLAC and venetoclax regimen was less toxic to normal peripheral blood mononuclear cells and bone marrow cells relative to leukemic samples and exhibited toxicity towards these normal cell types comparable to venetoclax+Ara-C and venetoclax+azacitidine. Mechanistically, combination treatment potently increased ceramides, synergistically disrupted mitochondrial membrane potential, and depleted several proteins that inhibit apoptosis, including XIAP and cIAP1.
    CONCLUSIONS: Overall, these data provide the rationale for additional mechanistic and preclinical in-vivo studies targeting AC and Bcl-2 in AML.
    Keywords:  AML; Bcl-2; acid ceramidase; acute myeloid leukemia; ceramide; sphingolipids
    DOI:  https://doi.org/10.1016/S2152-2650(22)01218-6
  17. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01282-4. [Epub ahead of print]22 Suppl 2 S243-S244
    AML-389 Phase 1/2 Study of SEL24/MEN1703, a First-in-Class Dual PIM/FLT3 Kinase Inhibitor, in Patients With IDH1/2-Mutated Acute Myeloid Leukemia: The DIAMOND-01 Trial.
    Giovanni Martinelli, Armando Santoro, Carlo Gambacorti-Passerini, Susana Vives Polo, Scott R Solomon, Sudipto Mukherjee, Ewa Lech-Maranda, Moshe Yair Levy, Agnieszka Wierzbowska, María Calbacho-Robles, Giovanni Marconi, Maria Benedetta Giannini, Isabel Cano, Laura Torres Miñana, Evelyn Acuña-Cruz, Noemi Angelosanto, Tariq I Mughal, Antonio Galleu, Simona Blotta, Farhad Ravandi, Pau Montesinos.
       CONTEXT: Mutations in the FLT3 tyrosine kinase and in IDH1/IDH2 (collectively IDHm) co-occur in up to 30% of adults with acute myeloid leukemia (AML). SEL24/MEN1703 is an orally available, first-in-class, dual PIM/FLT3 kinase inhibitor. Preliminary results from the phase 1/2 first-in-human DIAMOND-01 trial (NCT03008187) demonstrated antitumor activity of single-agent SEL24/MEN1703 in adult patients with relapsed/refractory (R/R) IDHm AML, where 3 of 8 IDHm patients responded.
    OBJECTIVE: To report the first safety and efficacy results from an additional expansion cohort of the DIAMOND-01 trial in 20 patients with R/R IDHm AML.
    DESIGN: DIAMOND-01 is a phase 1/2, open-label, multicenter study consisting of 2 parts: dose escalation and cohort expansion, including an additional expansion cohort (IDHm) that is ongoing.
    PATIENTS: Patients with R/R IDHm AML and no standard therapeutic options were eligible.
    INTERVENTION(S): Patients received the recommended dose of 125 mg SEL24/MEN1703 orally, once daily for 14 days over a 21-day cycle until disease progression or unacceptable toxicity.
    MAIN OUTCOME MEASURE(S): The number and frequency of adverse events (AEs; primary) and overall response rate (ORR; secondary).
    RESULTS: As of 10 January 2022, 14 patients were enrolled in the IDHm cohort. Seven patients had IDH2, 1 had IDH1/2, and 4 had IDH1 mutations. Two patients had a concomitant FLT3-ITD mutation. Safety data (N=12) showed that grade ≥3 TEAEs (≥10% of patients) were pneumonia (33%) and asthenia (17%), both unrelated to the study drug. Of the 7 patients who completed ≥1 treatment cycle and had ≥1 post-baseline assessment or clear disease progression, ORR was 28.6%; 1 patient achieved a complete response with incomplete blood count recovery at cycle 3 and underwent hematopoietic stem cell transplant, and 1 patient had a partial response at cycle 4 (confirmed at cycle 7 and still on treatment). Among the 7 remaining patients, 3 discontinued before completion of cycle 1 without progression or response, and 4 patients are ongoing and have not yet undergone post-baseline assessments.
    CONCLUSIONS: SEL24/MEN1703 had a manageable safety profile and single-agent activity in adult patients with R/R IDHm AML and may be a feasible therapeutic option in this difficult-to-treat population.
    Keywords:  AML; FLT3-ITD, FLT3 inhibitor; IDH mutation; PIM kinase; Trial-in-Progress; acute myeloid leukemia
    DOI:  https://doi.org/10.1016/S2152-2650(22)01282-4
  18. J Cancer Res Clin Oncol. 2022 Sep 28.
    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.
    Study Alliance Leukemia (SAL)
       PURPOSE: Higher 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.
    METHODS: Patients 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.
    RESULTS: Six-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.
    CONCLUSIONS: This 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 REGISTRATION: NCT03188874.
    Keywords:  Acute myeloid leukemia; Consolidation therapy; Cytarabine dosage; Real-world data
    DOI:  https://doi.org/10.1007/s00432-022-04356-9
  19. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01300-3. [Epub ahead of print]22 Suppl 2 S253-S254
    AML-464 Tolerability and Efficacy of the First-In-Class Anti-CD47 Antibody Magrolimab Combined With Azacitidine in Frontline Patients With TP53-Mutated Acute Myeloid Leukemia (AML): Phase 1b Results.
    Naval Daver, Paresh Vyas, Suman Kambhampati, Monzr Al Malki, Richard Larson, Adam Asch, Gabriel Mannis, Wanxing Chai-Ho, Tiffany Tanaka, Terrence Bradley, Deepa Jeyakumar, Eunice Wang, Guan Xing, Mark Chao, Giri Ramsingh, Camille Renard, Indu Lal, Joshua Zeidner, David Sallman.
       CONTEXT: Patients with TP53-mutated AML have a poor prognosis. Magrolimab is an antibody blocking CD47, a "don't eat me" signal on cancer cells, which induces tumor phagocytosis and is synergistic with azacitidine.
    OBJECTIVE: Report final tolerability and efficacy data.
    DESIGN: Ph1b single-arm trial of magrolimab+azacitidine (NCT03248479).
    PATIENTS: 72 frontline patients with TP53-mutated AML unsuitable for intensive chemotherapy.
    INTERVENTIONS: Magrolimab IV 1-mg/kg (priming) then 30-mg/kg ramp-up QW/Q2W (maintenance). Azacitidine 75 mg/m2 IV/SC days 1-7 (each 28-day cycle).
    MAIN OUTCOME MEASURES: Primary endpoints were safety/tolerability and complete remission (CR) rate.
    RESULTS: Common treatment-emergent adverse events (TEAEs) were constipation (52.8%), diarrhea (47.2%), febrile neutropenia (45.8%), nausea (43.1%), fatigue (37.5%), decreased appetite (37.5%), thrombocytopenia (31.9%), peripheral edema (30.6%), and cough (30.6%). Common grade (G)≥3 TEAEs were febrile neutropenia (37.5%), anemia (29.2%; G3, 26.4%; G4, 2.8%), thrombocytopenia (29.2%), pneumonia (26.4%), and neutropenia (20.8%). G3 hemolysis was reported in 1 patient; no G4 hemolysis was reported. Objective response rate was 48.6% (CR, 33.3%; CR with incomplete hematologic recovery [CRi]/CR with partial hematologic recovery [CRh], 8.3%; morphologic leukemia-free state [MLFS], 1.4%; partial remission, 5.6%). 16.7% and 5.6% of patients had stable disease and progressive disease (PD), respectively; 30- and 60-day mortality rates were 8.3% and 18.1%, respectively. Response assessments were unavailable in 4.2% (discontinued due to AEs) and 6.9% (other) of patients prior to the C3D1 assessment. Median time to CR/CRi was 2.2 months (range, 1.7-7.2) and CR was 3.0 months (range, 1.8-9.6); 14/31 (45.2%) evaluable patients with CR/CRi/CRh/MLFS achieved negative MRD. 8/24 patients with CR had a longitudinal TP53 variant-allele-frequency (VAF) assessment; 5/8 (63%) had ≤5% VAF. Treatment was stopped due to stem cell transplant (9 [12.5%]), PD (26 [36.1%]), death (8 [11.1%]), AE (13 [18.1%]), or other (14 [19.4%]). Median durations of CR and CR/CRi were 7.7 (95% CI, 4.7-10.9) and 8.7 (95% CI, 5.3-10.9) months, respectively. Median overall survival was 10.8 months (95% CI, 6.8-12.8; 8.3-month median follow-up).
    CONCLUSIONS: Magrolimab+azacitidine showed durable responses and encouraging overall survival in frontline patients with TP53-mutated AML unsuitable for intensive chemotherapy. A Ph3 trial of magrolimab+azacitidine vs standard-of-care in TP53-mutated AML (ENHANCE-2; NCT04778397) is ongoing.
    Keywords:  AML; CD47; TP53, Phase I; acute myeloid leukemia; azacitidine; magrolimab
    DOI:  https://doi.org/10.1016/S2152-2650(22)01300-3
  20. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01266-6. [Epub ahead of print]22 Suppl 2 S236
    AML-326 Novel FLT3-ALK2 Dual Inhibitor TP-0184 Inhibits Leukemia Growth by Targeting Serine Biosynthesis in FLT3-ITD-Positive AML Cells.
    Anudishi Tyagi, Stanley Ly, Bin Yuan, Fouad El-Dana, Appalaraju Jaggupilli, Jason Foulks, Steven Warner, V Lokesh Battula.
       CONTEXT: FMS-like tyrosine kinase 3 (FLT3) internal tandem duplication (ITD) inhibitors have been studied; however, molecular factors contributing to this resistance are unknown.
    OBJECTIVE: i) To investigate the clinical significance of BMP type 1 receptor ALK2 in AML patients with FLT3-ITD mutations. ii) To elucidate the therapeutic effect of FLT3-ALK2 dual inhibitor TP-0184 on leukemia growth.
    METHODS: To determine whether ALK2 is a potential target in FLT3-mutated AML patients, we analyzed OHSU and TCGA datasets. We treated AML cell lines with FLT3-WT or -ITD mutations with ALK2 inhibitors and measured their effect on cell cycle and proliferation. To determine the mechanism of TP-0184, we measured the activation of FLT3 downstream signaling by using western blotting and RNA sequencing. Further, we performed kinase profiling to understand the binding specificity of TP-0184 with 11 different FLT3 mutants. Finally, we investigated the effect of TP-0184 on AML growth in vivo using FLT3-mutated PDX and xenograft models.
    RESULTS: Analysis of AML datasets showed that ALK2 is significantly upregulated in AML patients with FLT3 mutations compared to those with WT-FLT3 (P<0.00001) and predicts poor overall survival (P=0.05). Treatment of FLT3-WT and -mutated AML cell lines with the ALK2 inhibitors LDN-212854 and TP-0184 resulted in significant inhibition of FLT3-ITD-mutant cell growth at low concentrations (IC50<25 nM), while WT-FLT3 cells were affected only at high concentrations (IC50>100 nM). Interestingly, TP-0184 induced G1/G0 arrest in AML cell lines with FLT-ITD mutations but had minimal to no effect in FLT3-WT AML cells. Further, we observed that treatment with TP-0184 in AML cell lines significantly inhibited multiple signaling proteins downstream of FLT3, such as p-STAT5 and p-ERK, as well as p-PI3K, p-mTOR, and p-S6K. Gene expression analysis revealed that treatment with TP-0184 in FLT3-ITD cell lines significantly downregulated the serine biosynthesis pathway. Lastly, treatment with TP-0184 significantly prolonged the survival of FLT3-ITD-mutated AML-bearing mice (P<0.0001).
    CONCLUSIONS: Our data indicate that ALK2 is a prognostic marker in FLT3-mutated AML. TP-0184 inhibits cell proliferation by inhibiting FLT3 downstream signaling pathways in AML cells. Kinase assays confirmed that TP-0184 is a highly specific FLT3-ALK2 dual inhibitor. TP-0184 inhibits AML growth in FLT3-mutated PDX and xenograft models.
    Keywords:  ACVR1; ALK2; AML; BMP signaling; FLT3-ITD; TP-0184
    DOI:  https://doi.org/10.1016/S2152-2650(22)01266-6
  21. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01379-9. [Epub ahead of print]22 Suppl 2 S295-S296
    CML-395 Efficacy and Safety Results From ASCEMBL, a Phase III Study of Asciminib vs. Bosutinib in Patients With Chronic Myeloid Leukemia in Chronic Phase (CML-CP) After ≥2 Prior Tyrosine Kinase Inhibitors (TKIs): Week 96 Update.
    Delphine Réa, Andreas Hochhaus, Michael J Mauro, Yosuke Minami, Elza Lomaia, Sergey Voloshin, Anna Turkina, Dong-Wook Kim, Jane F Apperley, Jorge E Cortes, Andre Abdo, Laura Marie Fogliatto, Dennis Dong Hwan Kim, Philipp le Coutre, Susanne Saussele, Mario Annunziata, Timothy P Hughes, Naeem Chaudhri, Lynette Chee, Valentin García-Gutiérrez, Koji Sasaki, Shruti Kapoor, Alex Allepuz, Sara Quenet, Véronique Bédoucha, Carla Boquimpani.
       CONTEXT: Asciminib is the first BCR::ABL1 inhibitor to Specifically Target the ABL Myristoyl Pocket (STAMP). In the ASCEMBL primary analysis, among patients with CML-CP after ≥2 prior TKIs, asciminib resulted in improved major molecular response (MMR, 25.5% vs. 13.2%) at week 24 and fewer grade ≥3 adverse events (AEs) or AEs leading to treatment discontinuations compared with bosutinib. After a median follow-up of 2.3 years, we report updated efficacy and safety results (data cutoff: October 6, 2021).
    OBJECTIVE: To compare the MMR rate at week 96 with asciminib vs. bosutinib.
    DESIGN: A phase III, multicenter, open-label study of adults with CML-CP after ≥2 prior TKIs randomized 2:1 to asciminib 40 mg twice daily or bosutinib 500 mg once daily and stratified by baseline major cytogenetic response (MCyR).
    RESULTS: In total, 233 patients were randomized to receive asciminib (n=157) or bosutinib (n=76). At data cutoff, treatment was ongoing in 84 (53.5%) and 15 (19.7%) patients, respectively; the most common reason for discontinuation was lack of efficacy in 38 (24.2%) and 27 (35.5%) patients, respectively. The key secondary objective was met; MMR rate at week 96 was higher with asciminib (37.6%) than with bosutinib (15.8%). The difference after adjusting for MCyR was 21.7% (95% CI, 10.5%-33.0%; 2-sided P=.001). At week 96, more patients receiving asciminib than bosutinib had BCR::ABL1IS ≤1% (45.1% vs. 19.4%). Responses were durable, with a probabilities (95% CI) of maintaining MMR and BCR::ABL1IS ≤1% for ≥72 weeks of 96.7% (87.4%-99.2%) and 94.6% (86.2%-97.9%), respectively, with asciminib and 92.9% (59.1%-99.0%) and 95.0% (69.5%-99.3%), respectively, with bosutinib. Median time to treatment failure was 24 months with asciminib and 6 months with bosutinib. Asciminib had longer duration of exposure (103.1 vs. 30.5 weeks) but fewer AEs leading to treatment discontinuation (7.7% vs. 26.3%) than bosutinib.
    CONCLUSIONS: After >2 years of follow-up, asciminib demonstrated durable responses by continuing to show superior efficacy and better safety/tolerability vs. bosutinib. MMR more than doubled with asciminib over bosutinib, and the difference in MMR rates increased between the 2 arms from 12.2% at week 24 to 21.7% at week 96. These results support the use of asciminib as a new CML therapy.
    Keywords:  ASCEMBL; CML; Phase III; TKI; Trial-in-Progress; asciminib
    DOI:  https://doi.org/10.1016/S2152-2650(22)01379-9
  22. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01225-3. [Epub ahead of print]22 Suppl 2 S215-S216
    AML-131 ERG: From a Fortuitous Discovery to Potential Treatment for AML.
    Eitan Kugler, Shreyas Madiwale, Darren Yong, Yehudit Birger, Julie Ai Thoms, David B Sykes, Muhammad Yassin, Nasma Aqaqe, Avigail Rein, Hila Fishman, Ifat Geron, Chun-Wei Chen, Brian Raught, Qiao Liu, Michael Milyavsky, John Pimanda, Gilbert G Privé, Shai Izraeli.
       BACKGROUND: The ETS transcription factor ERG is essential for the maintenance of hematopoietic stem cells. However, it has also been implicated as an oncogene in the development of acute leukemia. Our studies and those of others have demonstrated that ERG directly contributes to the initiation and maintenance of lymphoid and myeloid acute leukemia subtypes. Nevertheless, ERG co-factors critically involved in leukemogenesis remain largely uncharacterized.
    AIMS: Here we report a critical role for the conserved amino-acid proline at position 199, at the 3' end of the PNT domain, for ERG's leukemogenic activity.
    DESIGN AND RESULTS: We specifically demonstrate in functional and gene expression assays that P199 is required for ERG-induced myeloid differentiation restriction and for self-renewal and maintenance of murine hematopoietic stem and progenitor cells (HSPC). To identify key protein interactions associated with leukemia progression induced by ERG, we used proximity ligation-mass spectrometry. The proximity maps of wildtype (WT)-ERG and mutated form of ERG at position 199 (P199L-ERG) were compared in HEK293 cells. Most significantly, the mutation severely impaired ERG's interaction with components of the NCoR-HDAC3 complex, resulting in a 40% reduction in the number of spectral counts in comparison with WT-ERG. ChIP-sequencing for histone markers conducted on ER-Hoxb8 cells (murine GMPs) demonstrated a decrease in H3K27ac signature at over 1500 unique sites in cells transduced with WT-ERG compared to those transduced with the mutant. Interestingly, these sites were predominantly associated with enhancers of genes expressed in mature myeloid cells. Furthermore, in gene expression assays conducted on ER-Hoxb8 cells stably expressing human ERG and treated with an HDAC3 inhibitor, myeloid differentiation genes and pathways associated with acute leukemia were most affected. Finally, we examined the significance of the ERG/NCoR-HDAC3 interaction in human leukemia models. Targeting HDAC3 using pharmacological and genetic tools led to a significant antileukemic effect in NSG mice transplanted with ERG-dependent human leukemia lines.
    CONCLUSIONS: Our findings indicate that the aberrant overexpression of ERG maintains HSPCs in an undifferentiated state and promotes AML development. We suggest that the interaction between ERG and the NCoR-HDAC3 complex has an important role in the leukemogenic process, and that HDAC3 inhibition could be beneficial in AML characterized by high ERG expression.
    Keywords:  AML; ERG; HDAC3; Leukemia
    DOI:  https://doi.org/10.1016/S2152-2650(22)01225-3
  23. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01212-5. [Epub ahead of print]22 Suppl 2 S208-S209
    AML-029 Quizartinib Prolonged Overall Survival (OS) vs Placebo Plus Intensive Induction and Consolidation Therapy Followed by Single-Agent Continuation in Patients Aged 18-75 Years With Newly Diagnosed FLT3-Internal Tandem Duplication Positive (FLT3-ITD+) Acute Myeloid Leukemia (AML).
    Harry Erba, Pau Montesinos, Radovan Vrhovac, Elzbieta Patkowska, Hee-Je Kim, Pavel Zak, Po-Nan Wang, Tsvetomir Mitov, James Hanyok, Li Liu, Aziz Benzohra, Arnaud Lesegretain, Jorge Cortes, Alexander Perl, Mikkael Sekeres, Hervé Dombret, Sergio Amadori, Jianxiang Wang, Mark Levis, Richard Schlenk.
       OBJECTIVES: Quizartinib is an oral, potent, selective, type II FLT3 inhibitor with prolonged OS as a single-agent in relapsed/refractory FLT3-ITD+ AML. We report results from the global, randomized, double-blind, phase 3 QuANTUM-First trial (NCT02668653), evaluating quizartinib plus standard induction and post-remission consolidation (including allogeneic hematopoietic cell transplant [allo-HCT] in first complete remission [CR1]) followed by single-agent continuation (up to 3 years) vs placebo plus chemotherapy in newly diagnosed FLT3-ITD+ AML.
    METHODS: Patients 18-75 years with newly diagnosed FLT3-ITD+ AML received induction with cytarabine 100 or 200 mg/m2/day (days 1-7) and daunorubicin 60 mg/m2/day or idarubicin 12 mg/m2/day (days 1-3). Patients were randomized to quizartinib (40 mg/day [days 8-21]) or placebo; stratified by region, age, and white blood cell count at diagnosis. Patients with CR or CR with incomplete hematologic recovery (CRi) received up to 4 cycles of high-dose cytarabine plus quizartinib (40 mg/day) or placebo and/or allo-HCT followed by continuation with quizartinib (30-60 mg/day) or placebo (up to 3 years). The primary endpoint was OS.
    RESULTS: Between September 2016 and August 2019, 539 patients were randomized (quizartinib [n=268], placebo [n=271]). Median age was 56 years (range, 20-75 years). As of August 2021 (median follow-up, 39.2 months), 58 patients remained on continuation. Median OS was significantly longer with quizartinib vs placebo (31.9 vs 15.1 months; HR, 0.776; 95% CI, 0.615-0.979; 2-sided P=.0324). CR+CRi rates were 71.6% and 64.9%, respectively. Allo-HCT in CR1 was performed in 157 patients (quizartinib, 31%; placebo, 27%). When censored for allo-HCT, OS trended longer with quizartinib vs placebo (HR, 0.752; 95% CI, 0.562-1.008; 2-sided P=.055). Relapse-free survival was longer with quizartinib vs placebo (HR, 0.733; 95% CI, 0.554-0.969). Grade ≥3 adverse events (AEs) were similar across arms. Discontinuations due to AEs occurred in 20.4% (quizartinib) and 8.6% (placebo). Fifty-six patients died from treatment-emergent AEs (quizartinib, 11.3%; placebo, 9.7%); mostly infections. Grade 3/4 electrocardiographic QT prolongation occurred in 3.0% (quizartinib) and 1.1% (placebo).
    CONCLUSIONS: Quizartinib plus standard therapy, followed by continuation, including after allo-HCT, for up to 3 years was tolerable with statistically significant and clinically meaningful OS improvements in adults ≤75 years with newly diagnosed FLT3-ITD+ AML.
    Keywords:  AML; FLT3-ITD; Phase III; acute myeloid leukemia; adult
    DOI:  https://doi.org/10.1016/S2152-2650(22)01212-5
  24. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01276-9. [Epub ahead of print]22 Suppl 2 S240-S241
    AML-348 A Phase Ib/II Study of Ivosidenib With Venetoclax +/- Azacitidine in IDH1-Mutated Hematologic Malignancies.
    Curtis Lachowiez, Gautam Borthakur, Sanam Loghavi, Zhihong Zeng, Tapan Kadia, Lucia Masarova, Koichi Takahashi, George Tippett, Jacqueline Garcia, Prithviraj Bose, Elias Jabbour, Farhad Ravandi, Naval Daver, Guillermo Garcia Manero, Paresh Vyas, Hagop Kantarjian, Marina Konopleva, Courtney DiNardo.
       CONTEXT: IDH1-mutated (IDH1+) myeloid malignancies depend on the anti-apoptotic protein BCL-2 for survival. Combining the IDH1 inhibitor ivosidenib (IVO) with the BCL-2 inhibitor venetoclax (VEN) may improve outcomes. We report the completed P1b portion of a P1b/II study investigating IVO (500 mg PO daily D15-continuous) with VEN (D1-14), with or without azacitidine (AZA; 75 mg/m2 D1-7) every 28 days.
    OBJECTIVES: Primary P1b objectives included safety, tolerability, and IWG-defined overall response (ORR: CR+CRi+CRh+PR+MLFS).
    DESIGN: A dose-escalation/-de-escalation study evaluating cohorts of 6 patients enrolled within 4 dose levels: DL1 (IVO+VEN 400 mg), DL2 (IVO+VEN 800 mg), DL3 (IVO+VEN 400 mg+AZA), DL4 (IVO+VEN 800 mg+AZA).
    PARTICIPANTS: Eligible patients were ≥ age 18 with IDH1+ MDS, newly diagnosed (ND) or relapsed/refractory (R/R) AML.
    RESULTS: Thirty-one patients enrolled with a median follow-up of 26 months. The median age was 67 years (range: 44-84), 71% had AML (ND: N=14, R/R: N=8), and 29% had MDS. ELN risk was intermediate or adverse in 19% and 55%, respectively (N=17). The ORR was 94% (DL1: 67%, DL2-DL4: 100%); composite CR (CRc: CR+CRi+CRh) was 87% (DL1: 67%, DL2: 100%, DL3: 85%, DL4: 100%). Of the AML patients, 60% attained measurable residual disease-negative CRc by multiparameter flow cytometry. IDH1+ mutation clearance by digital droplet PCR (sensitivity: 0.1%-0.25%) occurred in 64% of patients following cycle 5. Grade 3-5 adverse events (AEs) in ≥ 10% of patients included febrile neutropenia (29%) and pneumonia (23%). AEs of special interest (AESI) included grade 3 tumor lysis syndrome in 2 (dose-limiting toxicity in 1), and differentiation syndrome in 4 (G2: N=2, G3: N=2) patients. All AESIs were transient and reversible. Median EFS and OS were 36 and 42 months, respectively, and 24-month OS was 71% (95% CI: 55-91; ND-AML: 67%, R/R-AML: 50%, MDS: 100%). MRD-negative CRc improved OS (median NR vs. 8 months, P: 0.002) in ND- and R/R-AML. Based on efficacy and toxicity, DL3 (IVO+VEN400+AZA) was the recommended phase 2 dose.
    CONCLUSIONS: IVO+VEN±AZA is an effective treatment for IDH1+ myeloid malignancies with an expected toxicity profile and notable activity across disease groups. Single-cell sequencing and CyTOF correlatives will also be presented.
    Keywords:  AML; IDH1; Phase I/II; ivosidenib; targeted-therapy; venetoclax
    DOI:  https://doi.org/10.1016/S2152-2650(22)01276-9
  25. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01274-5. [Epub ahead of print]22 Suppl 2 S239-S240
    AML-342 A Phase II Study of Azacitidine and Venetoclax as Maintenance Therapy in Patients With Acute Myeloid Leukemia.
    Alexandre Bazinet, Hagop Kantarjian, Gautam Borthakur, Musa Yilmaz, Prithviraj Bose, Elias Jabbour, Yesid Alvarado, Kelly Chien, Naveen Pemmaraju, Koichi Takahashi, Nicholas Short, Naval Daver, Ghayas Issa, Nitin Jain, Debra Bull-Linderman, Courtney DiNardo, Guillermo Montalban-Bravo, Guillermo Garcia-Manero, Koji Sasaki, Farhad Ravandi, Tapan Kadia.
       CONTEXT: Patients with acute myeloid leukemia (AML) who achieve remission but do not undergo stem cell transplantation (SCT) experience high relapse rates. Oral azacitidine (CC-486) prolongs relapse-free survival (RFS) and overall survival (OS) in SCT-ineligible patients. The addition of venetoclax may enhance the efficacy of azacitidine within a maintenance regimen.
    OBJECTIVE: Establish the efficacy and tolerability of maintenance azacitidine and venetoclax in AML.
    DESIGN: This is a phase 2, single-center, single-arm study ongoing since 9/2019. The current median follow-up time is 9 months.
    PATIENTS: AML patients ≥18 years in first remission (CR1) after induction and 1+ consolidation cycles not immediately eligible for SCT were eligible. High- and low-intensity induction regimens were permitted. Patients in CR2 and beyond were eligible if minimal residual disease (MRD)-positive.
    INTERVENTIONS: Azacitidine 50 mg/m2 IV/SQ x5 days and venetoclax 400 mg x14 days (or 7 days at the discretion of the treating physician in patients at high risk of cytopenias/infections) were administered in 28-day cycles, up to 24 cycles.
    MAIN OUTCOME MEASURES: RFS (enrollment to death/relapse), OS, and safety/tolerability. Patients who later became eligible for SCT were censored at the time of SCT.
    RESULTS: Thirty-four patients with a median age of 54 years (19-82) have been enrolled (25 after intensive induction, 9 after low-intensity induction). Thirteen (38%) received 14 days of venetoclax and 21 (62%) received 7 days. The median number of cycles given was 8 (1-24). To date, 9 patients (26%) have relapsed and 6 (18%) have died (all following relapse or SCT). The median RFS was not reached (NR) (1-yr 62.4%) and the median OS was NR (1-yr 84.2%). Eight patients (24%) went off protocol for SCT. Median RFS stratified by ELN 2017 was NR (1-yr 83.1%), NR (1-yr 65.6%), and 4 months in ELN favorable, intermediate, and adverse, respectively. Two of the 7 (29%) MRD(+) patients became MRD(-) on maintenance. The most common grade 3/4 adverse events were infections (26%, including 6% neutropenic fever), thrombocytopenia (21%), and neutropenia (18%).
    CONCLUSIONS: Azacitidine/venetoclax is tolerable and yields encouraging RFS in AML patients not immediately eligible for SCT.
    Keywords:  AML; Phase II; acute myeloid leukemia; azacitidine; maintenance therapy; venetoclax
    DOI:  https://doi.org/10.1016/S2152-2650(22)01274-5
  26. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01228-9. [Epub ahead of print]22 Suppl 2 S217
    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).
    Naval G Daver, Andrew H Wei, Eytan M Stein, Daniel J DeAngelo, Dhrubajyoti Pathak, Yunnan Xu, Stephanie Grzesiak, Adriano Venditti.
       CONTEXT: 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).
    OBJECTIVE: 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).
    DESIGN: The study will consist of a safety run-in (part 1) and an expansion phase (part 2).
    PATIENTS: 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).
    INTERVENTIONS: 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.
    MAIN OUTCOME MEASURES: 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.
    Keywords:  AML; acute myeloid leukemia; azacitidine; clinical trial; p53; trial-in-progress; venetoclax
    DOI:  https://doi.org/10.1016/S2152-2650(22)01228-9
  27. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01214-9. [Epub ahead of print]22 Suppl 2 S209-S210
    AML-055 Outcomes Based on Sequential Use of Venetoclax Based Therapy and Targeted Therapy in Acute Myeloid Leukemia (AML).
    Maximilian Stahl, Rory M Shallis, Andriy Derkach, Aaron D Goldberg, Anthony Stein, Eytan M Stein, Guido Marcucci, Amer M Zeidan, Shai Shimony, Daniel J DeAngelo, Richard M Stone, Ibrahim Aldoss, Brian J Ball, Jan Phillip Bewersdorf.
       CONTEXT: Treatment options for patients with AML have expanded with the approval of targeted therapies including FLT3 and IDH1/IDH2 inhibitors and venetoclax-based therapies. However, therapeutic efficacy based on alternate sequencing of these agents is not well described yet. In addition, little is known regarding molecular predictors of response to targeted therapy after venetoclax-based therapy and for the reverse sequence.
    OBJECTIVE: The objective of this study was to describe the efficacy of targeted therapies following venetoclax-based therapy and contrast it with the efficacy of venetoclax post-targeted therapy in AML.
    DESIGN: In this multicenter, retrospective cohort study, we included 97 patients who received venetoclax-based therapy preceding (n=53) or following treatment with FLT3, IDH1 or IDH2 inhibitors (n=44) at 3 academic cancer centers in the United States.
    MAIN OUTCOME MEASURES: Response to therapy was determined using the 2017 European LeukemiaNet response criteria for AML The overall response rate (ORR) was defined as a composite of complete response (CR), CR with incomplete count recovery (CRi), partial remission (PR) and morphologic leukemia-free state (MLFS). Overall survival (OS) was calculated from the time of initiation of venetoclax, FLT3, IDH1, or IDH2 inhibitor therapies.
    RESULTS: Among patients treated with venetoclax after targeted agents, the ORR was 59.5% (CR: 19%) with a median OS of 9.2 months. Conversely, use of FLT3 (n=31), IDH1 (n=5) or IDH2 (n=17) inhibitors following venetoclax yielded an ORR of 17.7% and median OS of 4.2 months. Eight of 9 patients responding to targeted agents after venetoclax received gilteritinib. Univariate analysis demonstrated mutations in TP53 (hazard ratio [HR] for death: 44.99; 95% CI: 2.81 - 719.42; p<0.001) and KRAS (HR: 3.05; 95% CI: 1.05 - 8.86; p=0.035) to be associated with shorter OS in the targeted agent group, while FLT3-ITD mutations were associated with a shorter median OS (HR: 3.25; 95% CI: 1.55-6.79; p=0.002) in the venetoclax-treated cohort.
    CONCLUSIONS: Venetoclax can be an effective salvage therapy in patients previously treated with targeted therapy. However, while the FLT3 inhibitor gilteritinib retained clinical efficacy in patients previously treated with venetoclax, IDH1/2 inhibitors had very limited efficacy suggesting that alternative therapeutic strategies should be considered for these patients.
    Keywords:  AML; response; sequencing of therapy; targeted therapy; venetoclax
    DOI:  https://doi.org/10.1016/S2152-2650(22)01214-9
  28. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01305-2. [Epub ahead of print]22 Suppl 2 S256
    AML-488 Impact of Somatic Mutations on Treatment Response and Outcomes in Patients With Core Binding Factor Acute Myeloid Leukemia.
    Somedeb Ball, Akriti G Jain, Parth Patel, Chen Wang, Luis E Aguirre, Zaker I Schwabkey, Mohammad Hussaini, Onyee Chan, Seongseok Yun, Andrew T Kuykendall, Eric Padron, Kendra Sweet, Jeffrey E Lancet, Rami S Komrokji, David A Sallman.
       CONTEXT: Prognostic significance of somatic mutations remains unclear in patients with core binding factor acute myeloid leukemia (CBF-AML), especially with advanced next generation sequencing (NGS) and measurable residual disease (MRD) detection techniques.
    OBJECTIVES: To estimate the distribution of mutations and to assess their impact on outcomes in CBF-AML.
    DESIGN: Single-center retrospective study Patients: Adults with newly diagnosed CBF-AML Main Outcome Measures: MRD negativity, relapse free survival, overall survival Results: Our study includes 59 patients (mean age- 48 years) with CBF-AML [t(8;21), n=21 and Inv(16), n=38], with available NGS and CBF-MRD results during primary treatment. Most common mutations at diagnosis included KIT (31%), NRAS (26%), KRAS (15%), FLT3-TKD (11%), and FLT3-ITD (9%). Mutations in NRAS were enriched (32%) in Inv(16) AML, whereas KIT mutations were common (45%) in association with t(8;21). No pathogenic mutation was noted in 17% of patients. Most common induction regimen was "7+3" (48%), followed by "7+3+GO" (37%), with 36% receiving gemtuzumab ozogamicin (GO) in consolidation (median- 3 cycles). CBF-MRD negativity was 15% at the end of induction, which increased to 70% after consolidation, with no significant difference between patients with or without common kinase mutations (KIT, RAS, or FLT3). In the t(8;21) AML, CBF-MRD negativity rate was lower in KIT-mutant vs. wild type (38% vs. 75%) patients, although it was not statistically significant (p = 0.31). Overall, 23 (39%; 14 on CR1) patients underwent allogeneic stem cell transplant (allo-SCT), with no difference in respect to baseline mutations. The rate of relapse (n = 10; 17%) was also similar with or without ≥ 1 of KIT, RAS, or FLT3 mutations. The presence of any of these 3 mutations was associated with worse relapse free survival (7.7 vs. 12.9 months; p= 0.01), with no significant difference in overall survival (median OS- 94.1 months vs. not reached, p=0.44). Overall, patients with CBF-AML did well independent of induction/consolidation regimen, inclusion of GO, achievement of MRD negativity, or allo-SCT status, with a 2-year OS of > 80%.
    CONCLUSIONS: Mutations in KIT, RAS, and FLT3 are enriched in CBF-AML and contribute to earlier relapse although OS remains favorable across molecular and treatment subgroups.
    Keywords:  AML; FLT3; Inv(16); RAS; core binding factor; relapse free survival
    DOI:  https://doi.org/10.1016/S2152-2650(22)01305-2
  29. Br J Haematol. 2022 Sep 28.
    Truncated CSF3 receptors induce pro-inflammatory responses in severe congenital neutropenia.
    Patricia A Olofsen, Dennis A Bosch, Hans W J de Looper, Paulina M H van Strien, Remco M Hoogenboezem, Onno Roovers, Vincent H J van der Velden, Eric M J Bindels, Emma M De Pater, Ivo P Touw.
      Severe congenital neutropenia (SCN) patients are prone to develop myelodysplastic syndrome (MDS) or acute myeloid leukaemia (AML). Leukaemic progression of SCN is associated with the early acquisition of CSF3R mutations in haematopoietic progenitor cells (HPCs), which truncate the colony-stimulating factor 3 receptor (CSF3R). These mutant clones may arise years before MDS/AML becomes overt. Introduction and activation of CSF3R truncation mutants in normal HPCs causes a clonally dominant myeloproliferative state in mice treated with CSF3. Paradoxically, in SCN patients receiving CSF3 therapy, clonal dominance of CSF3R mutant clones usually occurs only after the acquisition of additional mutations shortly before frank MDS or AML is diagnosed. To seek an explanation for this discrepancy, we introduced a patient-derived CSF3R-truncating mutation in ELANE-SCN and HAX1-SCN derived and control induced pluripotent stem cells and compared the CSF3 responses of HPCs generated from these lines. In contrast to CSF3R-mutant control HPCs, CSF3R-mutant HPCs from SCN patients do not show increased proliferation but display elevated levels of inflammatory signalling. Thus, activation of the truncated CSF3R in SCN-HPCs does not evoke clonal outgrowth but causes a sustained pro-inflammatory state, which has ramifications for how these CSF3R mutants contribute to the leukaemic transformation of SCN.
    Keywords:  CSF3R mutation; leukaemia; pro-inflammatory signalling; severe congenital neutropenia
    DOI:  https://doi.org/10.1111/bjh.18477
  30. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01371-4. [Epub ahead of print]22 Suppl 2 S291
    CML-288 Impact of ASXL1 Mutations on Prognosis of Chronic Phase Chronic Myeloid Leukemia.
    Aram Bidikian, Hagop Kantarjian, Elias Jabbour, Nicholas Short, Farhad Ravandi, Ghayas Issa, Koji Sasaki.
       CONTEXT: Mutations in ABL1 are established risk factors for therapy resistance in chronic phase chronic myeloid leukemia (CML-CP). However, much less is known about the impact of other cancer-associated gene mutations.
    OBJECTIVE: Study the prevalence and clinical impact of cancer-associated gene mutations in CML-CP.
    DESIGN: We screened our databases for CML-CP patients who were tested with a targeted next-generation sequencing panel that included 81 genes recurrently mutated in hematologic malignancies. Event-free survival (EFS) was measured from treatment initiation to the time of an event defined as loss of hematologic response, loss of major cytogenetic response (MCyR), lack of MCyR after 12 months, or transformation to accelerated/blast phase. Failure-free survival (FFS) was measured similarly, with the additional events of drug discontinuation due to adverse effects or no response. We subsequently performed univariate and multivariate analyses.
    RESULTS: The median age of patients was 60 years (18-80) and 46% were female. The most common first-line therapy was dasatinib (52%), followed by imatinib (19%), dasatinib + venetoclax (16%), and other TKIs (13%). The distribution of evaluable patients to low, intermediate, and high Sokal groups was 21%, 61%, and 18%, respectively. Cancer mutations were found in 23/68 patients (34%). The most common mutations involved ASXL1 (10/68 patients; 15%), DNMT3A (5/68 patients; 7%), and RUNX1 (3/68 patients; 4%). Mutations were also detected in ASXL2, CALR, EZH2, GNAS, IDH2, SF3B1, SMC3, SRSF2, STAG2, and SUZ12. Unlike mutations in other genes, patients with ASXL1 mutations had worse EFS compared to the no-mutation group (median of 33 vs. 88 months; P=0.002) and worse FFS (median of 14 vs. 58 months; P=0.04). There was no difference in overall survival by mutational status. In a multivariate analysis, mutated ASXL1 was independently associated with worse EFS (HR of 4.42; 95% CI 1.63-11.99). There was a non-statistically significant trend of lower molecular response rates and longer times to response (TTR) in ASXL1-mutated patients compared to wild-type (major molecular response rate of 78% vs. 82%; P=0.7 with median TTR of 17.5 vs. 9.2 months; P=0.5).
    CONCLUSIONS: Mutations in ASXL1 are associated with delayed responses and worse outcomes when detected in CML-CP.
    Keywords:  ASXL1, prognosis; CML; chronic myeloid leukemia
    DOI:  https://doi.org/10.1016/S2152-2650(22)01371-4
  31. Oncogene. 2022 Sep 28.
    HMG20B stabilizes association of LSD1 with GFI1 on chromatin to confer transcription repression and leukemia cell differentiation block.
    Alba Maiques-Diaz, Luciano Nicosia, Naseer J Basma, Isabel Romero-Camarero, Francesco Camera, Gary J Spencer, Fabio M R Amaral, Fabrizio Simeoni, Bettina Wingelhofer, Andrew J K Williamson, Andrew Pierce, Anthony D Whetton, Tim C P Somervaille.
      Pharmacologic inhibition of LSD1 induces molecular and morphologic differentiation of blast cells in acute myeloid leukemia (AML) patients harboring MLL gene translocations. In addition to its demethylase activity, LSD1 has a critical scaffolding function at genomic sites occupied by the SNAG domain transcription repressor GFI1. Importantly, inhibitors block both enzymatic and scaffolding activities, in the latter case by disrupting the protein:protein interaction of GFI1 with LSD1. To explore the wider consequences of LSD1 inhibition on the LSD1 protein complex we applied mass spectrometry technologies. We discovered that the interaction of the HMG-box protein HMG20B with LSD1 was also disrupted by LSD1 inhibition. Downstream investigations revealed that HMG20B is co-located on chromatin with GFI1 and LSD1 genome-wide; the strongest HMG20B binding co-locates with the strongest GFI1 and LSD1 binding. Functional assays demonstrated that HMG20B depletion induces leukemia cell differentiation and further revealed that HMG20B is required for the transcription repressor activity of GFI1 through stabilizing LSD1 on chromatin at GFI1 binding sites. Interaction of HMG20B with LSD1 is through its coiled-coil domain. Thus, HMG20B is a critical component of the GFI1:LSD1 transcription repressor complex which contributes to leukemia cell differentiation block.
    DOI:  https://doi.org/10.1038/s41388-022-02471-y
  32. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01410-0. [Epub ahead of print]22 Suppl 2 S312
    MDS-416 Myelodysplastic Syndromes in Morocco: Evolution over 15 Years.
    Soukaina Douma, Mouna Lamchahab, Nizar Dahmaoui, Basma Fatih, Bouchra Oukkach, Mohamed Rachid, Meryem Qachouh, Siham Cherkaoui, Nissrine Khoubila, Abdellah Madani.
       INTRODUCTION: Myelodysplastic syndromes (MDS) are defined in the World Health Organization classification of tumors of hematopoietic and lymphoid tissues as a group of clonal hematopoietic cell diseases characterized by cytopenia, dysplasia in one or more of myeloid cell lines, ineffective hematopoiesis, and an increased risk of progression to acute myeloid leukemia (AML).
    OBJECTIVE: To determine the incidence of MDS in the pediatric hematology and oncology department of hospital 20 August 1953.
    PATIENTS AND METHODS: Descriptive retrospective study made at the Pediatric Hematology and Oncology Department of hospital 20 August 1953 of the CHU Ibn Rochd Casablanca, including all patients with MDS confirmed on myelogram or BOM, diagnosed between January 2014 and December 2018. Patients with CMML, MDS/MPS border syndromes, or AML were excluded from our study.
    RESULTS: We found 272 patients diagnosed with MDS over the 15-year period from January 2004 to December 2018. The median incidence of MDS in our study was 19 cases/year, the median age was 59.5 years. According to the age groups, we found that 108 patients (or 40%) represented the age group of young adults (31-60 years), 67 patients (or 25%) represented the age group of elderly subjects (61-74 years), 60 patients (20%) represented the age group of very old subjects (over 75 years). The sex ratio (M/F) is 0.74. We noted that 1% of patients were genetically exposed and 16% of patients were exposed to various risk factors. The history of autoimmune diseases was found in 18% of patients in our series. 91% of patients had clinical signs. Therapeutically, we found that 74% of patients received symptomatic treatment. Fifteen patients in our series received specific treatment. Median survival is 5.63 months Conclusions: Myelodysplastic syndromes present a heterogeneous group of clonal hemopathies characterized by peripheral cytopenias and the risk of progression to acute leukemia. Diagnosis is currently based on bone marrow cytology, but the contribution of cytogenetic and molecular biology seems to go beyond prognostic interest (early diagnosis, prediction of therapeutic response). While the treatment of low-risk myelodysplastic syndromes is based on the correction of cytopenias, that of high-risk myelodysplastic syndromes aims to control the leukemic clone.
    Keywords:  MDS; incidence; median survival; myelodysplastic
    DOI:  https://doi.org/10.1016/S2152-2650(22)01410-0
  33. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01253-8. [Epub ahead of print]22 Suppl 2 S229
    AML-250 Mitochondrial Respiration Regulates GPX4 Inhibition-Induced Ferroptosis in Acute Myeloid Leukemia.
    Hiroki Akiyama, Ran Zhao, Yuki Nishida, Lauren Ostermann, Poo Yee Mak, Edward Ayoub, Sujan Piya, Bing Carter, Michael Andreeff, Jo Ishizawa.
       CONTEXT: Ferroptosis, a form of non-apoptotic cell death regulated by iron-dependent lipid peroxidation, has drawn extensive attention as a potential anti-cancer strategy. However, it remains to be explored in hematologic malignancies. We here investigate the molecular mechanisms of ferroptosis in acute myeloid leukemia (AML) and its therapeutic potential of co-targeting mitochondrial respiration.
    RESULTS: Analyses of publicly available databases (TCGA, DepMap) showed that AML patients with higher mRNA expression of major anti-ferroptotic genes had significantly shorter survival and that leukemia cells are one of the cell types that are highly dependent on GPX4 among other cancers. This suggests the potential prognostic impact and relevance in therapeutics of this pathway in AML. Indeed, pharmacological inhibition or genetic knockdown of a well-established anti-ferroptosis regulator GPX4 induced profound ferroptosis, evidenced by dependency on iron and lipid peroxidation. Importantly, the induced cell death was agonistic of TP53 mutational status. As a potentially AML-specific mechanism that is unusual in solid tumor models, we found that GPX4 inhibition-induced ferroptosis was efficiently blocked by the mitochondria-targeted ubiquinone MitoQ in AML cells. Ubiquinone is an endogenous antioxidant protecting cells from lipid peroxidation, and in the mitochondria, the respiratory chain is essential for the recycling of ubiquinone. Thus, we hypothesized that mitochondria protect AML cells from ferroptosis by activating the ubiquinone cycle. Consistently, mitochondrial DNA-depleted HL60 Rho0 cells, which lack mitochondrial respiration, were more sensitive to ML210 compared to the parental cells. To translate this finding to a pharmacological approach, we utilized the imipridone ONC201, which hyperactivates mitochondrial protease ClpP to degrade mitochondrial proteins, including the respiratory chain complex, and exerts cancer-selective lethality (Ishizawa et al. Cancer Cell 2019). Indeed, the combination of ONC201 and ML210 resulted in synergistic anti-leukemia effects in primary AML cells. The combinatorial effect was also validated by utilizing genetically engineered AML cells (genetic knockdown of GPX4 or overexpression of hyperactivated mutant ClpP).
    CONCLUSIONS: GPX4 inhibition induces ferroptosis involving mitochondrial redox machinery in AML. Combinatorial targeting of mitochondrial respiration with GPX4 inhibition exerts synergistic anti-leukemia effects. Further studies are in progress to assess the molecular mechanisms and the in-vivo efficacy of the combinatorial treatments.
    Keywords:  AML; ClpP; GPX4; ferroptosis; mitochondrial respiration
    DOI:  https://doi.org/10.1016/S2152-2650(22)01253-8
  34. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01255-1. [Epub ahead of print]22 Suppl 2 S230
    AML-256 A Phase 1 Study of Gilteritinib in Combination With Induction and Consolidation Chemotherapy in Patients With Newly Diagnosed Acute Myeloid Leukemia: Final Study Results.
    Keith W Pratz, Mohamad Cherry, Nikolai A Podoltsev, Jessica K Altman, Alexander E Perl, Brenda W Cooper, Joseph G Jurcic, Tara L Lin, Gary J Schiller, Ruishan Wu, Jason E Hill, Stanley C Gill, Angela James, Elizabeth Shima Rich, Nahla Hasabou, Mark J Levis.
       CONTEXT: Gilteritinib, an oral FLT3 inhibitor, demonstrated antileukemic responses in patients with FLT3mut+ relapsed/refractory AML.
    OBJECTIVE: Present final data from a phase 1 study of once-daily gilteritinib plus intensive chemotherapy in newly diagnosed (ND) AML.
    DESIGN: This 4-part, open-label study (NCT02236013) assessed gilteritinib dose/schedule and effects of alternative anthracycline treatment.
    INTERVENTION: Gilteritinib plus 7+3 induction with idarubicin or daunorubicin, plus ≤3 cycles of high-dose cytarabine and gilteritinib consolidation, and 2 years of single-agent gilteritinib maintenance treatment post consolidation or transplant.
    PATIENTS: Adults with ND AML; FLT3 mutation not required for enrollment (known core binding factor fusions excluded).
    MAIN OUTCOME MEASURES: Safety, tolerability, PK, antileukemic effects.
    RESULTS: Eighty patients were allocated to gilteritinib (safety analysis set, n=78 [age 23-77 y]; FLT3mut+, n=44 [FLT3-ITD, n=33]). Median follow-up was 37.7 months. On-study HSCT was performed in 27/80 (33.8%) patients (FLT3mut+, 26/44 [59.1%]). Dose-limiting toxicities occurred in 15/78 (19.2%) patients (200-mg/d cohort: neutropenia, n=1; neutropenic colitis, n=1). Maximum tolerated dose was 120 mg/d. Across the study, AEs led to gilteritinib discontinuation in 24.4% of patients. At end-of-treatment, composite complete remission (CRc: complete remission [CR] + CR with incomplete hematologic recovery [CRi] + CR with incomplete platelet recovery [CRp]), CR, CRi, and CRp rates were 79.7%, 54.4%, 21.5%, and 3.8%, respectively, in the overall population and 90.9%, 70.5%, 13.6%, and 6.8% among FLT3mut+ patients. In the overall (n=79) and FLT3mut+ populations (n=44), 60-day mortality rates were 1.3% and 0%, respectively, and median (95% CI) disease-free survival was 15.1 (9.5, 31.9) and 15.1 (4.9, 31.9) months. In the overall (n=69) and FLT3mut+ populations (n=41) receiving ≥80 mg/d, median (95% CI) OS was 38.6 (21.7, NE) and 45.9 (30.8, NE) months, respectively, and the estimated 3-year OS rate was 56.0% and 60.1%. Anthracycline choice did not substantially impact CRc rate or toxicity. In patients who achieved CRc with gilteritinib ≥120 mg/d, mutational clearance of FLT3-ITD (summed FLT3 ITD:wildtype signal ratio ≤10-4) after consolidation was 84.6% (11/13).
    CONCLUSIONS: Gilteritinib plus induction and consolidation chemotherapy was well tolerated and resulted in CR, FLT3-ITD clearance, and long-term survival in patients with ND FLT3mut+ AML, supporting ongoing randomized trials testing this approach against current standards.
    Keywords:  AML; FLT3, gilteritinib; Phase I; acute myeloid leukemia; adverse events; clinical response
    DOI:  https://doi.org/10.1016/S2152-2650(22)01255-1
  35. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01309-X. [Epub ahead of print]22 Suppl 2 S258
    AML-513 The Role of FLT3 Inhibitors in Patients With Acute Myeloid Leukemia (AML) and T(6;9)(P22;Q34).
    Faustine Ong, Tapan Kadia, Nicholas J Short, Musa Yilmaz, Yesid Alvarado, Koji Sasaki, Sherry A Pierce, Guillermo Garcia-Manero, Courtney DiNardo, Gautam Borthakur, Marina Konopleva, Naval Daver, Hagop Kantarjian, Farhad Ravandi.
       CONTEXT: Efficacy of FLT3 inhibitors (FLT3-i) in patients with AML and t(6;9)(p22;q34)/DEK-NUP214 is not well-established.
    OBJECTIVE: We compared overall survival (OS) and event-free survival (EFS) of AML patients with t(6;9) who received frontline FLT3-i, regardless of their FLT3 mutation status.
    DESIGN: We evaluated patients with AML or high-risk myelodysplastic syndrome (HR-MDS) seen in our center between 1995-2021. Among 9936 patients, 55 patients (0.5%) had t(6;9) (48 AML, 7 HR-MDS). Patients were divided according to their induction regimen with (n:5) or without FLT3-i (n:48).
    RESULTS: Among 47 patients, 35 were FLT3-ITD+, 5 had both ITD and TKD mutations. ITD allelic ratio (AR) was known for 28 (80%) patients (AR range: 0.01-0.95) with 11 (31%) patients having an AR ≥0.5. Age was well-balanced across both groups with median of 41 years. Ninety-two percent had ECOG performance status of 0-1 on presentation. Most patients in FLT3-i group (80%) and non-FLT3-i group (77%) received intensive chemotherapy. Sorafenib was used in 62% and quizartinib in 24% of cases. All patients in FLT3-i group and 71% in non-FLT3-i group were FLT3-ITD+. All patients in FLT3-i group achieved CR/CRi (60% MRD negative) as compared to 52% of non-FLT3-i group, and 60% of FLT3-i group had transplantation in CR1 (vs. 21% of non-FLT3-i). All groups received 1 cycle of therapy to reach CR/CRi. With median follow up of 47 months, 2-year OS and EFS were higher in FLT3-i than non-FLT3-i cohort (80% and 60% vs. 41% and 20%, respectively, p=0.2 for OS and 0.1 for EFS). Addition of FLT3-i improved 2-year EFS in FLT3-ITD+ patients (60% vs. 15% in non-FLT3-i regimen, p=0.07). Two-year OS and EFS were lower in FLT3-ITD+ patients than wild-type FLT3 patients (44% and 22% vs. 58% and 42%, respectively; p=0.4 for OS and 0.3 for EFS), regardless of FLT3-i therapy during induction. CR/CRi rate was similar between FLT3-ITD+ and wild-type FLT3 patients (57%) but more wild-type FLT3 patients received transplantation in CR1 (42%) than FLT3-ITD+ (23%).
    CONCLUSIONS: FLT3 mutation status does not impact survival in patients with t(6;9). Addition of FLT3-i in subset of patients with FLT3-ITD mutation is beneficial and should be further evaluated.
    Keywords:  AML; FLT3 inhibitor; FLT3-ITD; acute myeloid leukemia; chromosomal translocation
    DOI:  https://doi.org/10.1016/S2152-2650(22)01309-X
  36. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01260-5. [Epub ahead of print]22 Suppl 2 S233
    AML-283 The Genetic Landscape of NUP98-Rearranged Pediatric Leukemia.
    Masayuki Umeda, Nicole Michmerhuizen, Jing Ma, Tamara Westover, Michael P Walsh, Guangchun Song, Cristina Mecucci, Danika Di Giacomo, Franco Locatelli, Riccardo Masetti, Salvatore Nicola Bertuccio, Martina Pigazzi, Ilaria Iacobucci, Charles G Mullighan, Jeffery M Klco.
       CONTEXT: Rearrangements involving NUP98 are frequently found in pediatric acute myeloid leukemia (AML) and T-cell acute lymphoblastic leukemia (T-ALL) and are associated with poor prognosis. Various fusion partners have been identified; however, the genetic basis of how different fusion genes and cooperating mutations contribute to the disease phenotypes and the refractory nature remains to be clarified.
    OBJECTIVE: To elucidate the transcriptional and genetic background of pediatric NUP98-rearranged acute leukemia.
    DESIGN: Transcriptomic and genetic analyses were performed on pediatric leukemia with NUP98 rearrangements from multiple clinical studies at St. Jude Children's Research Hospital, by the Italian Association for Pediatric Hematology and Oncology, or by the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) initiative. No blinding was done in this study.
    PATIENTS: RNA sequencing from 95 patients (median age of 9.0 years) with NUP98-rearranged (NUP98r) leukemia was performed or obtained from previous studies. Eighty-one of these samples were also studied by tumor-normal-paired whole-genome or whole-exome sequencing.
    RESULTS: We identified 17 unique NUP98 fusion partners from RNAseq data with NSD1 as the most frequent partner (n=44, 46.3%), followed by KDM5A (n=27, 28.4%) and RAP1GDS1 (n=6, 6.3%). We also found rare fusion partners recurrent in this cohort, including LNP1, HOXA13, and HOXD13 (n=2, 2.1%, respectively). Among cooperating mutations, FLT3-ITD and WT1 were frequent in NSD1-AML (57.9% and 52.6%, respectively), and copy number loss of chromosome 13 harboring RB1 was found in 86.3% of NUP98-KDM5A AML with erythromegakaryocytic expression patterns (FAB M6-7). NUP98-RAP1GDS1 fusions are found in both AML (n=3) and T-ALL (n=3) cases and those with T lineage differentiation have concurrent NOTCH1 mutations, indicating that both fusions and cooperating mutations are contributing to the disease phenotypes. We further performed transcriptome analysis of NUP98r AML, integrating various AML subtypes from previous studies. NUP98r AML expressed high MEIS1, PRDM16, and HOXA-B cluster genes similar to AMLs with NPM1 or UBTF mutations, suggesting a molecular basis shared by these subtypes.
    CONCLUSIONS: Genomic and transcriptional profiling of pediatric NUP98-rearranged leukemia identified unique associations among fusions, cooperating mutations, and disease phenotypes.
    Keywords:  AML; NUP98; acute lymphoblastic leukemia; acute myeloid leukemia; genetics; pediatrics
    DOI:  https://doi.org/10.1016/S2152-2650(22)01260-5
  37. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01279-4. [Epub ahead of print]22 Suppl 2 S242
    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.
    Roberta Ranieri, Martin Neuenschwander, Sabrina Kleissle, Federica Mezzasoma, Serenella Silvestri, Alessio Ferrari, Sara Pierangeli, Serena Donnini, Francesca Milano, Marcella Sabino, Valentina Tini, Giulio Spinozzi, Brunangelo Falini, Jens Peter von Kries, Ilaria Gionfriddo, Maria Paola Martelli.
       CONTEXT: 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.
    OBJECTIVE: 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.
    METHODS: 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.
    RESULTS: 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).
    CONCLUSIONS: 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.
    Keywords:  AML; Aurora kinase A; NPM1; drug screening; targeted therapy
    DOI:  https://doi.org/10.1016/S2152-2650(22)01279-4
  38. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01287-3. [Epub ahead of print]22 Suppl 2 S246-S247
    AML-397 Integrated Safety Analysis of Tagraxofusp, a CD123-Directed Targeted Therapy, in Patients With Hematologic Malignancies.
    Naveen Pammaraju, Hagop Kantarjian, Kendra Sweet, Eunice S Wang, Andrew A Lane, Haris Ali, Anthony S Stein, Abdulraheem Yacoub, David Rizzieri, Sumithira Vasu, Vikas Gupta, Sangmin Lee, Gary J Schiller, James M Foran, Minakshi S Taparia, Todd L Rosenblat, Roland B Walter, Deborah Sieminski, Madhu Anant, Mrinal M Patnaik, Tariq I Mughal, Marina Konopleva.
       CONTEXT: The interleukin-3 receptor alpha chain (CD123), a cell-surface target, is aberrantly expressed on various myeloid neoplasms, including blastic plasmacytoid dendritic cell neoplasm (BPDCN), acute myeloid leukemia (AML), chronic myelomonocytic leukemia (CMML), and myelofibrosis (MF). Tagraxofusp (TAG, SL-401), a first-in-class CD123-targeted therapy, is the only treatment approved by the FDA and EMA for patients with BPDCN and is being investigated in AML, CMML, and MF.
    OBJECTIVE: To report the aggregated safety data for TAG monotherapy from trials in BPDCN, AML, CMML, and MF.
    DESIGN: An integrated safety analysis was performed for patients who received TAG monotherapy in three phase 1/2, multicenter clinical studies: Study 0114 (NCT02113982; BPDCN/AML), Study 0214 (NCT02270463; AML), and Study 0314 (NCT02268253; CMML/MF).
    SETTING: Hospitals and medical research institutions.
    PATIENTS: In total, 201 patients were included: BPDCN, n=86; AML, n=36; CMML, n=33; and MF, n=36.
    INTERVENTION(S): Patients received the recommended phase 2 TAG dose of 12 mcg/kg intravenously on days 1-3 (MF and CMML) or days 1-5 (BPDCN and AML).
    MAIN OUTCOME MEASURE(S): Treatment-related adverse events (TRAEs), adverse events (AEs) of interest, and discontinuations.
    RESULTS: As of July 2021, 11 (6%) patients discontinued TAG due to any-grade TRAEs. The most common any-grade TRAEs included hypoalbuminemia (41%), increased alanine (ALT; 40%) and aspartate (AST; 39%) aminotransferases, and thrombocytopenia (26%). The most common grade ≥3 TRAEs were thrombocytopenia (20%), increased AST (20%), and increased ALT (17%). Prolonged bone marrow suppression was not observed. Overall, 23% of patients experienced ≥1 serious TRAE. The onset of most TRAEs occurred in cycle 1 and was resolved by cycle 2. Capillary leak syndrome (CLS) occurred in 35 patients (17%), with onset usually within cycle 1. Most CLS events were non-severe (grade ≤2); 2 of 201 (1%) patients had a grade 5 event.
    CONCLUSIONS: This integrated analysis is the largest collation of safety data following treatment with TAG monotherapy. Most TRAEs were transient, and their frequency/severity decreased with increasing cycles. No myelosuppression or cumulative toxicity was reported following treatment over multiple cycles. These data confirm that the established and manageable safety profile of TAG monotherapy has been maintained in the 3 years following US approval.
    Keywords:  AML; Phase I/II; clinical data; myeloid malignancies; targeted therapy
    DOI:  https://doi.org/10.1016/S2152-2650(22)01287-3
  39. Exp Hematol Oncol. 2022 Sep 27. 11(1): 64
    Polyclonal evolution of Fanconi anemia to MDS and AML revealed at single cell resolution.
    Lixian Chang, Zejia Cui, Deyang Shi, Yajing Chu, Bichen Wang, Yang Wan, Qiuyi Ma, Ranran Zhang, Haoyuan Li, Xuelian Cheng, Tao Cheng, Xiaofan Zhu, Cheng Li, Weiping Yuan.
       BACKGROUND: Fanconi anemia (FA) is a rare disease of bone marrow failure. FA patients are prone to develop myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). However, the molecular clonal evolution of the progression from FA to MDS/AML remains elusive.
    METHODS: Herein, we performed a comprehensive genomic analysis using an FA patient (P1001) sample that transformed to MDS and subsequently AML, together with other three FA patient samples at the MDS stage.
    RESULTS: Our finding showed the existence of polyclonal pattern in these cases at MDS stage. The clonal evolution analysis of FA case (P1001) showed the mutations of UBASH3A, SF3B1, RUNX1 and ASXL1 gradually appeared at the later stage of MDS, while the IDH2 alteration become the dominant clone at the leukemia stage. Moreover, single-cell sequencing analyses further demonstrated a polyclonal pattern was present at either MDS or AML stages, whereas IDH2 mutated cell clones appeared only at the leukemia stage.
    CONCLUSIONS: We thus propose a clonal evolution model from FA to MDS and AML for this patient. The results of our study on the clonal evolution and mutated genes of the progression of FA to AML are conducive to understanding the progression of the disease that still perplexes us.
    Keywords:  Acute myeloid leukemia; Clonal evolution; Fanconi anemia; Myelodysplastic syndromes
    DOI:  https://doi.org/10.1186/s40164-022-00319-5
  40. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01288-5. [Epub ahead of print]22 Suppl 2 S247
    AML-399 A Phase 2, Open-Label, Multiarm, Multicenter Study to Evaluate Magrolimab Combined With Antileukemia Therapies for First-Line, Relapsed/Refractory, or Maintenance Treatment of Acute Myeloid Leukemia (AML).
    Paresh Vyas, Naval Daver, Mark Chao, Guan Xing, Camille Renard, Giri Ramsingh, David Sallman.
       CONTEXT: Patients with newly diagnosed AML who are ineligible for intensive chemotherapy (IC) are incurable, despite progress with azacitidine + venetoclax, whereas patients with relapsed/refractory disease continue to have a poor prognosis. Furthermore, relapse remains frequent for patients in remission receiving oral azacitidine. Magrolimab is a blocking antibody against CD47, a "don't eat me" signal overexpressed on cancer cells. This blockade induces tumor phagocytosis and is synergistic with chemotherapy and hypomethylating agents. Magrolimab + azacitidine has demonstrated encouraging efficacy in newly diagnosed AML (objective response rate [ORR], 63%; complete remission [CR], 42%).
    OBJECTIVE: To evaluate the safety/tolerability and efficacy of magrolimab combined with antileukemia therapies in patients with newly diagnosed or relapsed/refractory AML or with AML in maintenance post-IC.
    DESIGN: This open-label, multi-arm, multicenter study includes 3 safety run-ins with corresponding expansion cohorts (NCT04778410). Safety run-in cohorts will enroll 6 patients for 28 days to determine dose-limiting toxicities and the recommended phase 2 dose prior to enrollment of phase 2 cohorts.
    PATIENTS: Patients must be aged ≥75 or 18-74 years with comorbidities precluding IC (cohort [C]1), have relapsed/primary refractory disease post-IC (C2), or have CR/CR with incomplete hematologic recovery and measurable residual disease (MRD) post-IC (C3).
    INTERVENTIONS: Patients will receive magrolimab + venetoclax + azacitidine (C1), magrolimab + mitoxantrone + etoposide + cytarabine (MEC; C2), or magrolimab + CC-486 (C3). In all cohorts, magrolimab will be administered intravenously with priming and ramp-up doses of 1 (day [D]1, D4), 15 (D8), and 30 mg/kg (D11, D15, then QW [x5], followed by Q2W). Azacitidine, venetoclax, MEC, and CC-486 will be administered per label indications. After completion of the safety run-ins, additional patients will be enrolled into the phase 2 study (C1, n=40; C2, n=30; C3, n=40). Study treatments will follow the dosing schedule until disease progression, unacceptable toxicity, or loss of clinical benefit (C1/C3) or for 2 to 3 cycles for MEC with a maximum 12 months of magrolimab (C2).
    MAIN OUTCOME MEASURES: Primary efficacy endpoints are CR rate (C1/C2) and MRD-negative CR rate (C3). Secondary endpoints include overall survival, ORR, and MRD negativity (C1/C2).
    Keywords:  AML; CD47; Trial-in-Progress; acute myeloid leukemia; azacitidine; magrolimab; venetoclax
    DOI:  https://doi.org/10.1016/S2152-2650(22)01288-5
  41. BMC Cancer. 2022 Sep 24. 22(1): 1013
    The ABNL-MARRO 001 study: a phase 1-2 study of randomly allocated active myeloid target compound combinations in MDS/MPN overlap syndromes.
    MDS/MPN International Working Group
       BACKGROUND: Myelodysplastic/myeloproliferative neoplasms (MDS/MPN) comprise several rare hematologic malignancies with shared concomitant dysplastic and proliferative clinicopathologic features of bone marrow failure and propensity of acute leukemic transformation, and have significant impact on patient quality of life. The only approved disease-modifying therapies for any of the MDS/MPN are DNA methyltransferase inhibitors (DNMTi) for patients with dysplastic CMML, and still, outcomes are generally poor, making this an important area of unmet clinical need. Due to both the rarity and the heterogeneous nature of MDS/MPN, they have been challenging to study in dedicated prospective studies. Thus, refining first-line treatment strategies has been difficult, and optimal salvage treatments following DNMTi failure have also not been rigorously studied. ABNL-MARRO (A Basket study of Novel therapy for untreated MDS/MPN and Relapsed/Refractory Overlap Syndromes) is an international cooperation that leverages the expertise of the MDS/MPN International Working Group (IWG) and provides the framework for collaborative studies to advance treatment of MDS/MPN and to explore clinical and pathologic markers of disease severity, prognosis, and treatment response.
    METHODS: ABNL MARRO 001 (AM-001) is an open label, randomly allocated phase 1/2 study that will test novel treatment combinations in MDS/MPNs, beginning with the novel targeted agent itacitinib, a selective JAK1 inhibitor, combined with ASTX727, a fixed dose oral combination of the DNMTi decitabine and the cytidine deaminase inhibitor cedazuridine to improve decitabine bioavailability.
    DISCUSSION: Beyond the primary objectives of the study to evaluate the safety and efficacy of novel treatment combinations in MDS/MPN, the study will (i) Establish the ABNL MARRO infrastructure for future prospective studies, (ii) Forge innovative scientific research that will improve our understanding of pathogenetic mechanisms of disease, and (iii) Inform the clinical application of diagnostic criteria, risk stratification and prognostication tools, as well as response assessments in this heterogeneous patient population.
    TRIAL REGISTRATION: This trial was registered with ClinicalTrials.gov on August 19, 2019 (Registration No. NCT04061421).
    Keywords:  ABNL MARRO; ASTX727; Itacitinib; MDS/MPN; Phase 1b/2
    DOI:  https://doi.org/10.1186/s12885-022-10073-w
  42. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01220-4. [Epub ahead of print]22 Suppl 2 S212-S213
    AML-099 Prolonged XPO1 Inhibition Is Essential for Optimal Anti-Leukemic Activity in NPM1-Mutated AML.
    Giulia Pianigiani, Andrea Gagliardi, Valentina Tini, Barbara Bigerna, Simona Caruso, Andrea Marra, Sharon Shacham, Yosef Landesman, Concetta Quintarelli, Franco Locatelli, Maria Paola Martelli, Brunangelo Falini, Lorenzo Brunetti.
       INTRODUCTION: NPM1-mutated AML (NPM1c AML) is characterized by cytoplasmic delocalization of mutant NPM1 (NPM1c) and high expression of HOX genes, which are both mediated by XPO1 and critical for the leukemic phenotype. XPO1 inhibition by selinexor (seli) leads to NPM1c nuclear relocalization, loss of HOX expression, and terminal differentiation. However, 2 days/week seli did not result in evident benefit for NPM1c AML patients. We hypothesize that prolonged XPO1 inhibition is necessary to achieve optimal antileukemic activity. Since the newer XPO1 inhibitor eltanexor (elta) is given 5 days/week in early-phase clinical studies, we compared the antileukemic effects of intermittent (2d/w) and prolonged (5d/w) XPO1 inhibition in NPM1c AML models.
    METHODS: Parental OCI-AML3 cells and CRISPR-edited OCI-AML3 cells with endogenous NPM1 fused to GFP (NPM1c-GFP) were used for in vitro experiments. Patient-derived xenografts engineered to express Luciferase (PDX) were used for in vivo studies.
    RESULTS: We established the dynamics of NPM1c localization and HOX expression upon intermittent XPO1 inhibition. 12h incubation of NPM1c-GFP cells with seli resulted in NPM1c-GFP nuclear relocalization, but drug washout led to rapid NPM1c-GFP relocation into the cytoplasm. Next, we treated OCI-AML3 cells with seli for 24h only (short treatment, ST) or for 72h (continuous treatment, CT). RNA-seq at 72 hours in cells treated with CT demonstrated stable HOX downregulation, while ST did not result in significant changes in HOX expression. We then compared differentiation in cells treated with 2d/w and 5d/w XPO1 inhibition. 5d/w induced terminal differentiation of OCI-AML3 cells, while 2d/w treatment caused negligible differentiation. To confirm these results, we treated two PDXs with either seli (2 or 5d/w) or elta 5d/w for two weeks. In contrast to seli 2d/w, both 5d/w treatments induced near-complete loss of bone marrow AML engraftment, marked by HOX downregulation and differentiation. Finally, we established the effect of prolonged XPO1 inhibition on survival: mice treated for four consecutive weeks with elta 5d/w experienced significantly prolonged survival compared to vehicle.
    CONCLUSIONS: This study demonstrates that prolonged XPO1 inhibition is necessary to achieve optimal antileukemic activity and lays the groundwork for the design of new clinical trials with XPO1 inhibitors in NPM1c AML.
    Keywords:  AML; HOX genes; NPM1; XPO1; XPO1 inhibitors
    DOI:  https://doi.org/10.1016/S2152-2650(22)01220-4
  43. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01358-1. [Epub ahead of print]22 Suppl 2 S284-S285
    CML-046 Dose Modification Dynamics of Ponatinib in Patients With Chronic-Phase Chronic Myeloid Leukemia From the PACE and OPTIC Trials.
    Jane Apperley, Hagop Kantarjian, Michael Deininger, Elisabetta Abruzzese, Jorge Cortes, Charles Chuah, Daniel J DeAngelo, John DiPersio, Andreas Hochhaus, Jeffrey H Lipton, Frank Nicolini, Javier Pinilla-Ibarz, Delphine Rea, Gianantonio Rosti, Philippe Rousselot, Michael Mauro, Neil Shah, Moshe Talpaz, Alexander Vorog, Xiaowei Ren, Elias Jabbour.
       OBJECTIVE: In the PACE trial (NCT01207440), patients with resistant/intolerant chronic-phase chronic myeloid leukemia (CP-CML) demonstrated lasting responses to ponatinib 45 mg once daily (QD). The OPTIC trial (NCT02467270) prospectively evaluated a response-based dose-reduction strategy to optimize the dosing schedule of ponatinib in patients with CP-CML resistant to second-generation BCR::ABL1 tyrosine kinase inhibitor (TKI) therapy or with a T315I mutation. Our objective was to analyze dosing dynamics between the 2 trials and compare efficacy and safety outcomes.
    METHODS: In PACE, patients received an initial dose of ponatinib 45 mg QD. In OPTIC, patients were randomly assigned (1:1:1) to an initial oral dose of ponatinib 45 mg, 30 mg, or 15 mg QD. In PACE, proactive dose reductions were mandated as arterial occlusive events (AOEs) emerged as notable adverse events (AEs). In OPTIC, patients in the 45-mg and 30-mg cohorts in OPTIC achieving ≤1% BCR::ABL1IS had their doses reduced to 15 mg QD; doses were also reduced to manage AEs. Data from patients with CP-CML in PACE and from the 45-mg starting dose cohort in OPTIC were analyzed. Efficacy outcomes include ≤1% BCR::ABL1IS, progression-free survival (PFS), and overall survival (OS). Safety outcomes include treatment-emergent (TE) AEs and TE-AOE rates.
    RESULTS: A total of 364 CP-CML patients had ≥1 prior second-generation TKI or a T315I mutation and received a starting dose of ponatinib 45 mg (PACE, n=270; OPTIC, n=94). The percentages of patients with vascular disorders were 44% in PACE and 32% in OPTIC. The median follow-ups were 57 months (PACE) and 32 months (OPTIC). The ≤1% BCR::ABL1IS responses by 24 months were 52% (PACE) and 56% (OPTIC), 2-year PFS was 68% (PACE) and 80% (OPTIC), and 2-year OS was 86% (PACE) and 91% (OPTIC). Dose reductions due to AEs occurred in 82% (PACE) and 46% (OPTIC) of patients. Per 100 patient-years, exposure-adjusted TE-AOEs were 15.8 (PACE) and 7.6 (OPTIC) at 0 to <1 year.
    CONCLUSIONS: The response-based dose-reduction strategy in OPTIC resulted in comparable or better efficacy outcomes and fewer AE-related dose reductions and exposure-adjusted TE-AOEs, further demonstrating the benefit of the response-based dosing regimen used in OPTIC. This abstract is an encore from the European Hematology Association 2022 Annual Meeting.
    Keywords:  CML; T315I; TKI; leukemia; ponatinib
    DOI:  https://doi.org/10.1016/S2152-2650(22)01358-1
  44. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01229-0. [Epub ahead of print]22 Suppl 2 S217-S218
    AML-144 Uroporphyrinogen Decarboxylase (UROD) Is a Therapeutically Targetable Dependency in Acute Erythroid Leukemia.
    Jake Friske, Yu Fukuda, Emily Backhaus, Prady Baviskar, Francesca Benini, Jon Connelly, Jonathon Klein, Trevor Cunningham, Jiyang Yu, Shondra Pruett-Miller, John Schuetz, Charles Mullighan, Ilaira Lacobucci.
       CONTEXT: Acute erythroid leukemia (AEL) is a disease of erythroid lineage that commonly exhibits TP53 mutations, a complex karyotype, and poor prognosis irrespective of currently available therapies.
    OBJECTIVE: To identify AEL dependencies and novel therapeutic targets in AEL using genome-wide CRISPR/Cas9 knockout screens in mouse models of AEL.
    RESULTS: Analysis of the screens performed using the Brie library identified the Urod gene encoding uroporphyrinogen decarboxylase as a critical dependency in two Trp53/Bcor mutated mouse AEL cell lines. UROD is a cytosolic enzyme in the heme biosynthesis pathway involved in converting cytosolic uroporphyrinogen III into the key heme biosynthetic intermediate, coproporphyrinogen III. In an analysis of RNA-seq data from over 2,000 acute leukemia samples, UROD was significantly overexpressed and active by a data-driven network inference algorithm in AEL compared to other leukemia subtypes. We validated UROD as a dependency by electroporation of Cas9 and synthetic sgRNA ribonucleoprotein complex in the two screened cell lines, additional mouse leukemia cell lines, and two commercially available human AEL cell lines. Targeted knockout of UROD resulted in decreased tumor cell growth and viability compared to the non-targeting guide control cells. Sequencing analysis showed high editing efficiency (>85%) followed by recovery of the wildtype cells, indicating that UROD is a dependency in these cells. These results correlated with a significant increase of necrotic cells preceding loss of editing in the two tested human cell lines. We also observed an increase in ALAS1 expression, which is negatively regulated by cellular heme, indicating that UROD knockout leukemic cells cannot generate heme, leading to necrotic cell death. Moreover, mitochondrial function assays showed significant decreases in basal respiration, ATP production, maximal respiration, and spare capacity in a time-dependent manner, followed by the rescue of mitochondrial function after loss of editing efficiency and re-expression of UROD. We have recently developed homozygous UROD-dTAG engineered human AEL cell lines to perform in-vivo survival studies.
    CONCLUSIONS: Through whole-genome CRISPR knockout screening and functional studies, we show that UROD is a dependency in AEL and provides a basis for exploring its therapeutic inhibition.
    Keywords:  AEL; AML; RNP; UROD; heme synthesis
    DOI:  https://doi.org/10.1016/S2152-2650(22)01229-0
  45. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01388-X. [Epub ahead of print]22 Suppl 2 S300
    CML-466 Asciminib Provides Durable Molecular Responses in Patients With Chronic Myeloid Leukemia in Chronic Phase (CML-CP) With the T315I Mutation: Updated Efficacy and Safety Data From a Phase I Trial.
    Timothy P Hughes, Jorge E Cortes, Delphine Réa, Michael J Mauro, Andreas Hochhaus, Dong-Wook Kim, Koji Sasaki, Fabian Lang, Michael C Heinrich, Massimo Breccia, Michael Deininger, Yeow-Tee Goh, Jeroen J W M Janssen, Moshe Talpaz, Philipp le Coutre, Shruti Kapoor, Silvia Cacciatore, Fotis Polydoros, Nithya Agrawal, Francois-Xavier Mahon.
       CONTEXT: In CML-CP, the BCR::ABL1 T315I mutation confers resistance to previously approved ATP-competitive tyrosine kinase inhibitors (TKIs), except ponatinib and olverembatinib. In a previous analysis of the phase I, dose-escalation trial X2101, asciminib-a BCR::ABL1 inhibitor that binds to the ABL myristoyl pocket-demonstrated efficacy and a favorable safety profile in heavily pretreated patients with T315I-mutated CML. We report updated efficacy and safety data in patients with CML-CP with the T315I mutation (data cutoff: January 6, 2021).
    OBJECTIVE: Provide updated safety and efficacy data for patients with T315I-mutated CML-CP after added exposure.
    DESIGN: Patients with T315I-mutated CML-CP and treated with ≥1 prior TKI were enrolled and received asciminib 200mg twice daily (BID).
    RESULTS: 48 patients were included; 25 patients (52.1%) received ≥3 prior TKIs. At data cutoff, treatment was ongoing in 27 patients (56.3%). 45 of 48 patients were evaluable (BCR::ABL1IS >0.1% at baseline) for major molecular response (MMR); 3 were excluded for BCR::ABL1 atypical transcripts. Among evaluable patients, 19 (42.2%) achieved MMR by week 24 and 22 (48.9%) by week 96. Evaluable patients included 26 ponatinib-pretreated and 19 ponatinib-naive patients; 34.6% and 68.4%, respectively, achieved MMR by week 96. The probability of maintaining MMR for ≥96 weeks was 84% (95% CI, 68.1%-100.0%). 23 of 37 patients (62.2%) with BCR::ABL1IS >1% at baseline achieved BCR::ABL1IS ≤1% by week 96. The safety/tolerability profile of asciminib remained favorable after ≈9 months of added exposure (median duration of exposure, 2.08 years; range, 0.04-4.13 years). The most common (≥10%) grade ≥3 adverse events (AEs) were lipase increase (18.8%, all asymptomatic elevations) and thrombocytopenia (14.6%). Arterial occlusive events occurred in 4 patients (8.3%); none led to dose adjustment/interruption/discontinuation. AEs leading to discontinuation occurred in 5 patients (10.4%). Only 2 study deaths, both due to COVID-19, occurred in this patient population.
    CONCLUSIONS: After a median exposure of >2 years, asciminib monotherapy 200mg BID exhibited a sustained, favorable safety profile and clinical efficacy in patients with T315I-mutated CML-CP-a population with high unmet medical need. This updated analysis confirms asciminib as a treatment option for patients with T315I-mutated CML-CP, including those previously treated with ponatinib.
    Keywords:  CML; Phase I; T315I; TKI; asciminib; chronic myeloid leukemia
    DOI:  https://doi.org/10.1016/S2152-2650(22)01388-X
  46. Cancer Discov. 2022 Sep 28. pii: CD-22-0086. [Epub ahead of print]
    Distinct Tumor Necrosis Factor Alpha Receptors Dictate Stem Cell Fitness Versus Lineage Output in Dnmt3a-Mutant Clonal Hematopoiesis.
    Jennifer M SanMiguel, Elizabeth Eudy, Matthew A Loberg, Kira A Young, Jayna J Mistry, Kristina D Mujica, Logan S Schwartz, Timothy M Stearns, Grant A Challen, Jennifer J Trowbridge.
      Clonal hematopoiesis resulting from enhanced fitness of mutant hematopoietic stem cells (HSCs) associates with both favorable and unfavorable health outcomes related to the types of mature mutant blood cells produced, but how this lineage output is regulated is unclear. Using a mouse model of a clonal hematopoiesis-associated mutation, DNMT3AR882/+ (Dnmt3aR878H/+), aging-induced TNFα signaling was found to promote the selective advantage of mutant HSCs and stimulate production of mutant B lymphoid cells. Genetic loss of TNFα receptor TNFR1 ablated the selective advantage of mutant HSCs without altering their lineage output, while loss of TNFR2 resulted in overproduction of mutant myeloid cells without altering HSC fitness. These results nominate TNFR1 as a target to reduce clonal hematopoiesis and risk of associated diseases, and support a model wherein clone size and mature blood lineage production can be independently controlled to modulate favorable and unfavorable CH outcomes.
    DOI:  https://doi.org/10.1158/2159-8290.CD-22-0086
  47. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01267-8. [Epub ahead of print]22 Suppl 2 S236
    AML-327 Novel Anti-B7-H3 Blocking Antibody Enhances NK Cell-Mediated Cytotoxicity and Improves Outcomes in AML-Bearing Mice.
    Anudishi Tyagi, Stanley Ly, Fouad El-Dana, Bin Yuan, Appalaraju Jaggupilli, Sabrina Grimm, Laura Bover, Hans-Jorg Buhring, V Lokesh Battula.
       CONTEXT: B7-H3 is an immune checkpoint molecule that is overexpressed in various human malignancies. Several monoclonal antibodies (mAbs) targeting B7-H3 have shown promising results against solid tumors. However, B7-H3's role in AML remains unexplored.
    OBJECTIVE: i) To analyze the prognostic significance of B7-H3 in AML. ii) To investigate the immunomodulatory role of B7-H3 in AML in vitro and in vivo.
    DESIGN: We analyzed B7-H3 expression in 100 AML patients and 20 healthy donors by flow cytometry and tested for associations with clinical features. To investigate the role of B7-H3 in immunomodulation, B7-H3 was knocked down in AML cell lines using shRNA or using anti-B7-H3 blocking mAbs (T1-A5, HEK1B3A3, and 58B1A2). A human-mouse chimeric (chT-1A5) antibody was generated, and its binding site on B7-H3 protein was characterized by epitope mapping. Finally, we treated mice bearing AML cells with anti-B7-H3 antibodies and measured human AML engraftment with flow cytometry and bioluminescence imaging.
    RESULTS: Expression of B7-H3 was significantly higher in AML patients than in healthy donors (p<0.01) and in CD34+ AML cells than in CD34- cells (p<0.01). Clinically, we observed that high B7-H3 expression was associated with a poor prognosis. Furthermore, we observed that inhibition of B7-H3 expression or blocking of its activity in AML cells using a novel monoclonal antibody (T-1A5) significantly enhanced natural killer (NK) cell-mediated cytotoxicity in vitro and in vivo. Moreover, we observed that the human-mouse chimera of this antibody (ChT-1A5) induced dose-dependent cell-mediated cytotoxicity (ADCC) in B7-H3+ primary AML cells but not in normal hematopoietic cells, suggesting the specify of this antibody for AML cells. Epitope mapping using peptides derived from the B7-H3 protein identified the FG loop region as the binding site for the T1-A5 antibody. Finally, treatment with T-1A5 or chT-1A5 in combination with human NK cells significantly reduced leukemia burden and extended survival in AML xenograft and patient-derived xenograft models.
    CONCLUSIONS: Our data indicate that B7-H3 is overexpressed in AML and that an anti-B7-H3 antibody (T1-A5) not only blocks B7-H3's immunomodulatory function but also induces ADCC in AML cells in vitro and in vivo.
    Keywords:  AML; B7-H3; antibody-dependent cell-mediated cytotoxicity (ADCC); immunomodulation; monoclonal antibody
    DOI:  https://doi.org/10.1016/S2152-2650(22)01267-8
  48. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01359-3. [Epub ahead of print]22 Suppl 2 S285-S286
    CML-047 Post Hoc Analysis of Responses to Ponatinib in Patients With Chronic-Phase Chronic Myeloid Leukemia (CP-CML) by Baseline BCR::ABL1 Level and Baseline Mutation Status in the OPTIC Trial.
    Michael Deininger, Jane Apperley, Christopher Kevin Arthur, Charles Chuah, Andreas Hochhaus, Hugues de Lavallade, Jeffrey Lipton, Elza Lomaia, James McCloskey, Lori Maness, Michael Mauro, Beatriz Moraghi, Carolina Pavlovsky, Gianantonio Rosti, Philippe Rousselot, Maria Undurraga Sutton, Xiaowei Ren, Alexander Vorog, Jorge Cortes.
       OBJECTIVES: OPTIC (NCT02467270) is a Phase 2 trial evaluating the safety and efficacy of ponatinib in patients with CP-CML resistant to ≥2 TKIs or have a T315I mutation. We present a post hoc analysis of patient responses by baseline BCR::ABL1 level and mutation status.
    METHODS: Patients with CP-CML resistant to ≥2 TKIs or with the T315I mutation were randomized to ponatinib starting doses of 45 mg, 30 mg, and 15 mg once daily. Doses were reduced to 15 mg after achievement of ≤1% BCR::ABL1IS in the 45-mg and 30-mg cohorts. The primary endpoint is ≤1% BCR::ABL1IS at 12 months. In this analysis, outcomes are analyzed by baseline T315I mutation status and baseline BCR::ABL1 level in the intent-to-treat (ITT) population.
    RESULTS: 283 patients were randomized (45-mg/30-mg/15-mg cohorts: n=94/95/94). At baseline, 84.1% of patients had >10% BCR::ABL1IS; 23.8% had T315I mutation. Subanalysis showed that patients with T315I mutations in the 45-mg cohort had the highest ≤1% BCR::ABL1IS response rates (60%) by 3 years versus other cohorts. Across cohorts, 97 patients without T315I mutations achieved ≤1% BCR::ABL1IS. Median duration of response (mDoR) for patients with a T315I mutation at baseline was 27 months in the 45-mg cohort (n=15) and 12 months in the 30-mg cohort (n=5). For patients without T315I mutations, the mDoR was not reached. Across cohorts, 79% of patients who achieved ≤1% BCR::ABL1IS maintained this response during the study. The most common nonhematologic treatment-emergent adverse events (TEAEs) and hematological TEAEs in the ITT population for all cohorts combined were arterial hypertension (28%), headache (18%), lipase increase (17%), thrombocytopenia (40%), neutropenia (26%), and anemia (19%). Overall, 6.0% of patients experienced a treatment-emergent arterial occlusive event (TE-AOE); 4.6% experienced a Grade ≥3 TE-AOE.
    CONCLUSIONS: The OPTIC post hoc analysis showed clinical benefit across dosing regimens regardless of T315I mutation status at baseline; the 45-mg cohort showed the highest response rates regardless of baseline BCR::ABL1IS levels. Regardless of T315I mutation status, most patients were able to maintain their response after dose reduction upon achieving BCR::ABL1IS ≤1%. This abstract is an encore from the American Society of Hematology 2021 Annual Meeting.
    Keywords:  CML; T315I; TKI; leukemia; ponatinib
    DOI:  https://doi.org/10.1016/S2152-2650(22)01359-3
  49. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01221-6. [Epub ahead of print]22 Suppl 2 S213
    AML-108 SELECT-AML-1 Trial in Progress: A Phase 2 Study of Tamibarotene in Combination With Venetoclax and Azacitidine in Previously Untreated Adult Patients Selected for RARA-Positive AML who are Ineligible for Standard Induction Therapy.
    Suman Kambhampati, Alireza Eghtedar, Christine McMahon, Stephane de Botton, Arnaud Pigneux, Brian Ball, Gautam Borthakur, Angela Volkert, Joanie Aasen Gausman, Kristen Baker, Graeme Hodgson, Erica Warlick, David Roth, Michael Kelly, Daniel Pollyea, Eytan Stein.
       CONTEXT: RARA-positive AML is a novel, genomically defined subset with an actionable target for treatment with tamibarotene, an oral and selective RARα agonist (McKeown 2017). In a previous trial in RARA-positive newly diagnosed (ND) AML patients ineligible for standard induction therapy, tamibarotene/azacitidine led to a CR/CRi rate of 61% with a rapid onset of response. The combination was generally well tolerated with no increase in myelosuppression compared to azacitidine alone (de Botton 2020). Responses were observed irrespective of mutations or cytogenetic risk. Approximately one-third of ND unfit AML patients do not respond to venetoclax, and nearly all patients eventually relapse (DiNardo 2020). Translational data suggest that RARA positivity, found in approximately 30% of patients in this AML subset (Vigil 2017), enriches for monocytic features reported to be associated with venetoclax resistance (Fiore 2020, Pei 2019). This suggests that the blood-based RARA biomarker selects for patients who may respond to tamibarotene and may be less likely to respond to venetoclax/azacitidine.
    OBJECTIVES: The primary objectives are to characterize the safety of the combination and to compare the CR/CRi rate of tamibarotene/venetoclax/azacitidine versus venetoclax/azacitidine; the secondary objectives are to compare the CR rate, CR/CRh rate, duration of response, time to response, and overall survival.
    DESIGN: A phase 2, open-label, multi-center trial comparing the activity of tamibarotene/venetoclax/azacitidine with that of venetoclax/azacitidine in treatment-naive RARA+ unfit AML patients. This 3-part trial includes a safety lead-in, randomized efficacy study, and salvage arm. Following the safety lead-in, patients will be randomized 1:1 to receive tamibarotene/venetoclax/azacitidine or venetoclax/azacitidine. Clinical activity will be characterized by European LeukemiaNet criteria. Response rates and 95% exact binomial confidence intervals will be calculated by treatment group. In the salvage arm, tamibarotene will be added for patients randomized to venetoclax/azacitidine who experience progressive disease, treatment failure, or relapse.
    INTERVENTION: Patients will be treated with azacitidine at 75 mg/m2 IV/SC daily on days 1-7, venetoclax on days 1-28 per VENCLEXTA® (venetoclax) USPI, and tamibarotene 6 mg twice per day by mouth on days 8-28 of each 28-day cycle. SELECT-AML-1 (NCT04905407) opened in July 2021 with ongoing enrollment.
    SETTING: U.S. and France.
    Keywords:  AML; Trial-in-Progress; acute myeloid leukemia; clinical trial; retinoic acid receptor (RAR)
    DOI:  https://doi.org/10.1016/S2152-2650(22)01221-6
  50. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01182-X. [Epub ahead of print]22 Suppl 2 S193-S194
    ALL-090 Highly Effective Combination of FLT3 and BCL2 Inhibitors in a Preclinical Model of Lineage Ambiguous Leukemia.
    Lindsey Montefiori, Ilaria Lacobucci, Amit Budhraja, Jamila Moore, Rebekah Baskin, Rebekah DeVries, Emily Backhaus, Melissa Johnson, Walter Akers, Divyabharathi Chepyala, Cyrus Mehr, Aman Seth, Paul Mead, Joseph Opferman, Charles Mullighan.
       CONTEXT: Lineage ambiguous leukemias are rare leukemia subtypes with diagnostic and treatment challenges and poor outcomes. We recently described a new subtype of lineage ambiguous leukemia defined by aberrant BCL11B activation ("BCL11B-a") which included 30%-40% of T/myeloid mixed-phenotype acute leukemia (MPAL) and early T-cell precursor acute lymphoblastic leukemia (ETP-ALL) cases, as well as 8% of acute myeloid leukemia cases (Montefiori et al. Cancer Discovery 2021). Most cases (81%) harbored activating FLT3 mutations, and all showed high FLT3 expression in addition to significantly higher BCL2 expression than non-BCL11B-a cases, suggesting a therapeutic vulnerability.
    OBJECTIVE: To determine the efficacy of FLT3 and BCL2 inhibitors in treating BCL11B-a lineage ambiguous leukemia.
    RESULTS: Here, we treated a BCL11B-a patient-derived xenograft (PDX) (original diagnosis of T/myeloid MPAL, FLT3-ITD positive) with the FLT3 inhibitor gilteritinib and the BCL2 inhibitor venetoclax, either alone or in combination. Treating commenced once disease burden reached at least 108 p/sec/cm2/sr (radiance) by whole-body imaging and continued for 8 weeks. Single-agent venetoclax exhibited a short-lived effect, whereas gilteritinib monotherapy delayed leukemia growth compared to vehicle (vehicle: 6.5-13×1010 p/sec/cm2/sr; venetoclax: 3.8-7.1×1010 p/sec/cm2/sr; gilteritinib: 3.6-7.4×109 p/sec/cm2/sr at end of treatment). In contrast, combination treatment rapidly and stably reduced leukemic burden to pre-treatment levels (8.8×105-1.1×107 p/sec/cm2/sr at end of treatment). Despite this near clearance of disease in combination-treated animals, leukemia burden increased following drug removal, indicating the capacity of the disease to persist in the presence of sustained combination therapy, although it remained sensitive to re-treatment. Moreover, we demonstrated that gilteritinib+venetoclax effectively reduced leukemia burden in heavily engrafted animals (>1011 p/sec/cm2/sr at start of treatment), suggesting that this combination may be effective at diagnosis in patients with high leukemia burden.
    CONCLUSIONS: Here, we showed that the combination of FLT3 (gilteritinib) and BCL2 (venetoclax) inhibitors is highly effective at reducing leukemia burden in a preclinical model of BCL11B-a lineage ambiguous leukemia. This combination blocked leukemic growth in vivo and was effective in highly engrafted animals. Ongoing studies in additional PDXs and pharmacodynamic work will identify mechanisms of synergy and characterize the residual combination-treated population to better understand putative drug resistance mechanisms.
    Keywords:  ALL; BCL11B; MPAL; gilteritinib; lineage-ambiguous; venetoclax
    DOI:  https://doi.org/10.1016/S2152-2650(22)01182-X
  51. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01268-X. [Epub ahead of print]22 Suppl 2 S237
    AML-328 Phase 2 Study of ASTX727 (Decitabine/Cedazuridine) Plus Venetoclax in Patients With Relapsed/Refractory Acute Myeloid Leukemia or Previously Untreated, Older Adult Patients Unfit for Chemotherapy.
    Tareq Abuasab, Yesid Alvarado, Ghayas Issa, Rabiul Islam, Nicholas James, Musa Yilmaz, Nitin Jain, Lucia Masarova, Steven Kornblau, Elias Jabbour, Naveen Pemmaraju, Guillermo Montalban Bravo, Sherry Pierce, Courtney DiNardo, Tapan Kadia, Naval Daver, Marina Konopleva, Guillermo Garcia-Manero, Farhad Ravandi.
       CONTEXT: ASTX727 is an oral formulation of the fixed-dose combination of decitabine and cedazuridine (100 mg/35 mg).
    OBJECTIVE: To investigate whether a total oral regimen of ASTX727+venetoclax (ven) is feasible and safe.
    METHODS: Pts ≥18 with relapsed/refractory AML (R/R) or pts with AML aged ≥75 or 18-74 unfit for intensive chemotherapy (frontline; FL) were eligible. Other eligibility criteria included adequate renal and hepatic function and ECOG performance status (PS) ≤2. ASTX727 is administered on days 1-5 of each cycle and ven on days 1-28 of the 1st cycle (21 days in subsequent cycles). Ven is held if blast <5% on day 21±3 bone marrow.
    RESULTS: Between March 2021 and January 2022, 28 pts (15 FL,13 R/R) were treated. The median age is 75 years (range, 47-90); 81 in the FL cohort and 72 in the R/R cohort. Nine FL pts (60%) were ≥80 and 5 (30%) were 70-80 years. In the R/R cohort, 9 pts (69%) were 70-80 years. The median PS is 2. The R/R cohort had a median of 2 prior treatments (range, 1-4). In the FL cohort, 5 (33%) had normal and 6 (40%) a complex karyotype; 3 had other. In the R/R cohort, 15% had normal and 46% a complex karyotype and 31% had other. Mutations in the FL cohort were RUNX1 (33%), ASXL1 (33%), DNMT3A (7%), TET2 (40%), and TP53 (20%). Overall response in the FL cohort is 61% (4 complete response [CR], 4 CR with incomplete count recovery [Cri], 1 morphological leukemia-free state [MLFS], 3 non-responders) and 45% in the R/R cohort (2 CR, 2 CRi, 2 MLFS, 5 non-responders, 2 not-evaluable). Both cohorts received a median of 2 cycles (range, 1-5). With a median follow-up of 5 months, the median survival for the FL cohort has not been reached (range, 0.6-7.3) and is 7.2 (range, 0.8-7.3) months for the R/R cohort. Grade ≥3 adverse events were neutropenic infections in 3 (11%) and liver enzymes elevation in 1 (4%).
    CONCLUSIONS: ASTX727 and venetoclax combination is safe and feasible and demonstrates significant efficacy in pts unfit for chemotherapy. Research funding by Taiho.
    Keywords:  AML; ASTX27; Phase II; decitabine; unfit
    DOI:  https://doi.org/10.1016/S2152-2650(22)01268-X
  52. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01456-2. [Epub ahead of print]22 Suppl 2 S335-S336
    MPN-375 BET Inhibitor Pelabresib (CPI-0610) Combined With Ruxolitinib in Patients With Myelofibrosis - JAK Inhibitor-Naïe or With Suboptimal Response to Ruxolitinib - Preliminary Data From the MANIFEST Study.
    John Mascarenhas, Marina Kremyanskaya, Andrea Patriarca, Claire Harrison, Prithviraj Bose, Raajit K Rampal, Francesca Palandri, Timothy Devos, Francesco Passamonti, Gabriela Hobbs, Moshe Talpaz, Alessandro Vannucchi, Jean-Jacques Kiladjian, Srdan Verstovsek, Ron Hoffman, Mohamed E Salama, Dong Chen, Pietro Taverna, Alex Chang, Gozde Colak, Sandra Klein, Vikas Gupta.
       CONTEXT: Myelofibrosis is characterized by splenomegaly, symptoms, cytopenias, and bone marrow (BM) fibrosis. Pelabresib is an investigational, oral, small-molecule BET inhibitor designed to selectively inhibit the BD1 and BD2 bromodomains of BET proteins.
    OBJECTIVE: Evaluation of pelabresib combined with ruxolitinib in patients with myelofibrosis.
    DESIGN: In Arm 3 of the Phase 2 MANIFEST study (NCT02158858), JAKi-naïve myelofibrosis patients are treated with pelabresib combined with ruxolitinib. In Arm 2, myelofibrosis patients with suboptimal response to ruxolitinib are treated with pelabresib as 'add-on' to ruxolitinib (Arm 2A: transfusion-dependent [TD]; Arm 2B: non-TD). The primary endpoints are ≥35% spleen volume reduction (SVR35) at Week 24 for Arms 3 and 2B and TD to transfusion independence (TI) in Arm 2A. The key secondary endpoint is ≥50% total symptom score reduction (TSS50) at Week 24; in Arm 2A, SVR35 is an additional key secondary endpoint. BM biopsies to assess BM fibrosis and safety data are also evaluated.
    RESULTS: As of September 2021, at Week 24 in Arm 3 (N=84), 68% (57/84) of patients achieved SVR35 (median change: -50%), and 56% (46/82) of patients achieved TSS50 (median change: -59%). At Week 24 in Arm 2 (N=86), 20% (16/81; 17% in Arm 2A and 26% in Arm 2B) of patients achieved SVR35 (median change: -18%), and 37% (30/81) of patients achieved TSS50 (median change: -47%). In Arm 2A, the TD to TI rate was 16% (6/38). At Week 24, BM fibrosis improvement ≥ 1 grade was achieved in 28% (16/57) and 26% (12/47) of patients in Arms 3 and 2, respectively. Hematologic treatment-emergent adverse events (TEAEs) included thrombocytopenia, in 52% (≥Grade 3: 12%) and 52% (≥Grade 3: 33%) of patients, and anemia, in 42% (≥Grade 3: 35%) and 27% (≥Grade 3: 19%) of patients in Arms 3 and 2, respectively. Low-grade gastrointestinal TEAEs and respiratory infections were observed but rarely resulted in discontinuation.
    CONCLUSIONS: In ruxolitinib treatment-naïve and previously treated patients with myelofibrosis, pelabresib combined with ruxolitinib resulted in splenic and symptom responses and BM fibrosis improvement and was generally well tolerated. The Phase 3 MANIFEST-2 study is evaluating pelabresib combined with ruxolitinib in JAKi treatment-naïve patients with myelofibrosis (NCT04603495).
    Keywords:  BET; MPN; Trial-in-Progress; epigenetics; myelofibrosis; pelabresib; ruxolitinib
    DOI:  https://doi.org/10.1016/S2152-2650(22)01456-2
  53. Sci Rep. 2022 Sep 28. 12(1): 16218
    Multiparameter analysis of timelapse imaging reveals kinetics of megakaryocytic erythroid progenitor clonal expansion and differentiation.
    Vanessa M Scanlon, Evrett N Thompson, Betty R Lawton, Maria Kochugaeva, Kevinminh Ta, Madeline Y Mayday, Juliana Xavier-Ferrucio, Elaine Kang, Nicole M Eskow, Yi-Chien Lu, Nayoung Kwon, Anisha Laumas, Matthew Cenci, Kalyani Lawrence, Katie Barden, Shannon T Larsuel, Fiona E Reed, Gabriela Peña-Carmona, Ashley Ubbelohde, June P Lee, Shakthi Boobalan, Yvette Oppong, Rachel Anderson, Colby Maynard, Kaylie Sahirul, Callista Lajeune, Varsha Ivathraya, Tiffany Addy, Patricia Sanchez, Colin Holbrook, Andrew Tri Van Ho, James S Duncan, Helen M Blau, Andre Levchenko, Diane S Krause.
      Single-cell assays have enriched our understanding of hematopoiesis and, more generally, stem and progenitor cell biology. However, these single-end-point approaches provide only a static snapshot of the state of a cell. To observe and measure dynamic changes that may instruct cell fate, we developed an approach for examining hematopoietic progenitor fate specification using long-term (> 7-day) single-cell time-lapse imaging for up to 13 generations with in situ fluorescence staining of primary human hematopoietic progenitors followed by algorithm-assisted lineage tracing. We analyzed progenitor cell dynamics, including the division rate, velocity, viability, and probability of lineage commitment at the single-cell level over time. We applied a Markov probabilistic model to predict progenitor division outcome over each generation in culture. We demonstrated the utility of this methodological pipeline by evaluating the effects of the cytokines thrombopoietin and erythropoietin on the dynamics of self-renewal and lineage specification in primary human bipotent megakaryocytic-erythroid progenitors (MEPs). Our data support the hypothesis that thrombopoietin and erythropoietin support the viability and self-renewal of MEPs, but do not affect fate specification. Thus, single-cell tracking of time-lapse imaged colony-forming unit assays provides a robust method for assessing the dynamics of progenitor self-renewal and lineage commitment.
    DOI:  https://doi.org/10.1038/s41598-022-19013-x
  54. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01223-X. [Epub ahead of print]22 Suppl 2 S214
    AML-119 The Impact of Post-Remission Granulocyte Colony-Stimulating Factor (G-CSF) Use (G-CSFu) in the Phase 3 Studies of Venetoclax (Ven) Combination Treatments in Patients (Pts) With Newly Diagnosed Acute Myeloid Leukemia (AML).
    Courtney DiNardo, Keith Pratz, Panayiotis Panayiotidis, Xudong Wei, Vladimir Vorobyev, Àrpád Illés, Inho Kim, Vladimir Ivanov, Grace Ku, Catherine Miller, Meng Zhang, Fernando Tatsch, Jalaja Potluri, Xenia Schmidt, Christian Recher.
       CONTEXT: In VIALE-A (NCT02993523) and VIALE-C (NCT03069352), Ven+azacitidine (Aza) and low-dose cytarabine (LDAC), respectively, improved outcomes in pts with intensive chemotherapy (IC)-ineligble newly diagnosed AML.
    OBJECTIVE: To explore outcomes in pts with G-CSFu.
    DESIGN: VIALE-A/C, dosing and treatment schedule were previously described. G-CSFu was given per institutional practice. Pts who achieved complete remission (CR) or CR with incomplete hematologic recovery (CRi) were analyzed by G-CSFu.
    RESULTS: In VIALE-A/C, baseline demographics were similar in Ven-treated pts regardless of G-CSFu. In VIALE-A, 190/286 pts (66%) treated with Ven+Aza and 41/145(28%) pts treated with placebo (PBO)+Aza achieved CR/CRi; 93(49%) and 10(24%) pts with CR/CRi received G-CSF (median time to first G-CSFu[range], 36d[2-483] and 35d[4-127]), respectively. Median duration of response (mDOR) for CR/CRi (95% CI) was not reached (NR; 17.5-NR) and 12.9mo(7.9-17.3) in the Ven+Aza+G-CSF and Ven+Aza+non-G-CSF groups, respectively; DOR at 12mo was 67% and 53%. Among 164 evaluable pts, measurable residual disease response (MRD<10-3) was achieved by 67, of whom 38(57%) had G-CSFu. Median overall survival (mOS[95% CI) was NR(NR-NR) with Ven+Aza+G-CSF and was 21.1mo(15.2-NR) with Ven+Aza+non-G-CSF; 12-mo OS rates were 83% and 71%. Post-remission Gr ≥3 neutropenia and febrile neutropenia (FN) rates were 33%(n=31) and 39%(n=36) with Ven+Aza+G-CSF, and 29%(n=28) and 20%(n=19) with Ven+Aza+non-G-CSF, respectively. Median durations of post-remission Gr ≥3 neutropenia and FN were 12.5d and 8d (Ven+Aza+G-CSF), and 16d and 10.5d (Ven+Aza+non-G-CSF). In VIALE-C, 69/143 pts (48%) treated with Ven+LDAC and 9/68(13%) pts treated with PBO+LDAC achieved CR/CRi; 30(43%) and 2(22%) received G-CSF (median time to first G-CSFu[range], 30d[2-459] and 229d[169-289]), respectively. mDOR was 10.8(4.9-17.8) and 11.8mo(5.9-NR) in the Ven+LDAC+G-CSF and Ven+LDAC+non-G-CSF groups, respectively; DOR at 12mo was 45% and 49%. mOS was 20.8mo(11.9-NR) with Ven+LDAC+G-CSF and 13.7mo(10.8-NR) with Ven+LDAC+non-G-CSF; 12-mo OS were ~68% and ~57%; 9/64 evaluable pts achieved MRD<10-3, of whom 6(67%) had G-CSFu. Post-remission Gr ≥3 neutropenia and FN rates were 53%(n=16) and 23%(n=7) with Ven+LDAC+G-CSF, and 51%(n=20) and 8%(n=3) with Ven+LDAC+non-G-CSF, respectively. Median durations of post-remission Gr≥3 neutropenia and FN were 15d and 6d(Ven+LDAC+G-CSF), and 12.5d and 29d(Ven+LDAC+non-G-CSF).
    CONCLUSIONS: Gr ≥3 neutropenia and FN with G-CSFu trended towards shorter duration, without negative impact on DOR or OS.
    Keywords:  AML; BCL2; G-CSF; Phase III; acute myeloid leukemia; neutropenia
    DOI:  https://doi.org/10.1016/S2152-2650(22)01223-X
  55. Cell Death Discov. 2022 Sep 28. 8(1): 400
    The landscape of extrachromosomal circular DNA (eccDNA) in the normal hematopoiesis and leukemia evolution.
    Tiansheng Zeng, Wenhui Huang, Longzhen Cui, Pei Zhu, Qing Lin, Wenjuan Zhang, Junyi Li, Cong Deng, Zhihua Wu, Zeyong Huang, Zhiyong Zhang, Tingting Qian, Wei Xie, Min Xiao, Yingyu Chen, Lin Fu.
      Elevated extrachromosomal circular DNA (eccDNA) has been reported to accelerate tumor pathogenesis. Although the eccDNA profiles of other tumors have been established, the landscape of the eccDNA of acute myeloid leukemia (AML) has not been revealed. Our study first depicted the eccDNA profile of normal hematopoiesis and AML evolution by exploiting the ATAC-seq and RNA-seq data from nine healthy donors and 12 AML patients, which contained a total of 137 cell samples and 96 RNA-seq samples (including 16 blood cell types of the normal hematopoietic and AML hierarchies). We found the number of eccDNAs generally increased with the evolution of normal hematopoiesis and AML. The ecDNAs and ring chromosomes were found to reappear both in normal hematopoiesis and AML cells. Furthermore, we compared the eccDNAs of AML with normal cells. There were almost 300 AML-specific genes, including the known oncogenes NRAS, MCL1, EVI1, GATA2, WT1, and PAK1. And the ecDNA (chr11: 58668376-58826008) occurred in five out of 17 AML evolution-related cells, which was associated with the high expression of the GLYATL1 gene and the high expressed GLYATL1 was a poor prognostic factor. In conclusion, the eccDNA profiles of normal hematopoiesis and AML evolution were depicted and the recurrent eccDNAs we revealed might be utilized in the treatment of AML as biomarkers.
    DOI:  https://doi.org/10.1038/s41420-022-01189-w
  56. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01230-7. [Epub ahead of print]22 Suppl 2 S218
    AML-147 C-MYC Targeting by Degradation: Novel Dual c-Myc/GSPT1 Degrader GT19715 Exerts Profound Cell Kill In Vitro and In Vivo in Acute Myeloid Leukemia and Lymphomas.
    Yuki Nishida, Darah A Scruggs, Edward Ayoub, Tallie Patsilevas, Vivian R Ruvolo, Po Yee Mak, Bing Z Carter, Steffen Boettcher, Abhishek Maiti, Qianxiang Zhou, Zhaohui Yang, Honghua Yan, Liandong Ma, Michael Andreeff.
       OBJECTIVE: The oncoprotein c-Myc governs epigenome and transcriptome and is deregulated in 70% of all human cancers. MYC is highly expressed in TP53 mutant or venetoclax (ven) resistant AML (Sallman, Blood 2021, Nishida, ASH 2021). However, targeting c-Myc or the MYC pathway has not been met with success. PROTACs or cerebron E3 ligase modulators (CELMoDs) are attractive modalities to specifically target hitherto undruggable oncoproteins.
    DESIGN AND SETTING: We developed the first c-Myc degrader GT19630 (GT19715, the salt form of GT19630). We tested it in cell-free, cellular assays and in animal studies.
    RESULTS: GT19630 effectively degraded oncogenic c-Myc protein (IC50 = 1.5 nM) in HL-60 cells. C-Myc was effectively pulled down by biotinylated GT19630 in a cell-free, in vitro affinity purification assay; and a proteasome inhibitor ixazomib completely blocked c-Myc degradation. IC50 of GT19715 in HL-60 cells was 1.8 nM, being considerably lower than 40.2 nM, an IC50 of normal myeloid progenitors in CFU assay, suggesting a therapeutic window. GT19630 shares chemical properties with other CELMoDs and proteomic analyses revealed degradation of translation termination factor G1 to S phase transition proteins 1 (GSPT1), an important factor in LSC survival (Surka et al. Blood 2021). Indeed, GT19630 effectively degrades GSPT1 along with complete degradation of c-Myc in a xenograft model with HL-60 cells, and inhibits tumor growth at a dose as low as 0.3 mg/kg/bid. GT19630 had no effect on normal myeloid lineages in rats at 6 mg/kg. GT19715 eliminates circulating blasts and prolongs survival in the c-Myc-driven systemic Daudi leukemia/lymphoma model. Importantly, GT19715 induces cell killing independent of TP53 status, and baseline c-Myc protein levels significantly correlated with sensitivity to GT19715 in MOLM-13 cells with CRISPR engineered knockout or mutations of TP53 (R2 = 0.86, P = 0.02). We found that MV4;11 ven resistant (VR) cells demonstrated elevated protein levels of c-Myc, and GSPT1 and exhibited greater sensitivity to GT19715compared to ven-sensitive parental cells. Finally, GT19715 significantly reduced human CD45+ AML blasts compared to vehicle control in vivo in an AML PDX model.
    CONCLUSIONS: First results with the novel dual c-Myc/GSPT1 degrader GT19715 demonstrate promising preclinical anti-lymphoma and -leukemia efficacy, providing rationale for its clinical development.
    Keywords:  AML; CELMoDs; GSPT1; Myc degrader; Myc-driven lymphoma/leukemia
    DOI:  https://doi.org/10.1016/S2152-2650(22)01230-7
  57. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01265-4. [Epub ahead of print]22 Suppl 2 S235-S236
    AML-325 Prognostic Impact of RAS and C-KIT Mutations (Single vs. Multiple) in Core-Binding Factor Acute Myeloid Leukemia (CBF-AML) Treated With a Fludarabine, Cytarabine, and G-CSF (FLAG)- Based Regimen.
    Tareq Abuasab, Jatastu Senapati, Tapan Kadia, Farhad Ravandi, Courtney DiNardo, Naveen Pemmaraju, Maro Ohanion, Yesid Alvarado, Hagop Kantarjian, Gautam Borthakur.
       CONTEXT: Despite a favorable prognosis, 30%-50% of patients (pts) with CBF-AML eventually relapse. Both RAS and KIT mutations have been associated with poor outcomes.
    OBJECTIVE: We studied the prognostic impacts of RAS and KIT mutations, the number of mutations, and the impact of mutation status on the attainment of optimal PCR reductions at the end of induction and the end of treatment (EOT).
    METHODS: Pts ≥ 18 years with de novo CBF-AML treated with a FLAG-based regimen between 2013 and 2019 were included. RAS and KIT mutations were assessed by next-generation sequencing. PCR for disease-specific transcripts was monitored at the end of C1 and at EOT.
    RESULTS: Of 91 pts with CBF-AML evaluated, the median age was 52 years (range, 22-79 years), and 41 were women (45%). Inv 16 was identified in 53 pts (58%), and 38 had t (8;21). FLT3 mutation was identified in 26 pts (29%), 32 pts (35%) had RAS mutation (19 NRAS, 3 KRAS, and 10 both), and 30 pts (33%) had KIT mutation. Of 32 pts with RAS mutation, 16 (50%) had single mutation, and 16 (50%) had multiple mutations. Of 30 pts with KIT mutation, 25 pts (83%) had single mutation, and 5 pts (17%) had multiple mutations. On regression analysis examining the presence of KIT or RAS mutation and their impacts on the end of induction and EOT PCR, only KIT mutations were associated with lower odds (0.33, 95% CI 0.11-0.9) of optimal EOT response. Among mutated pts, the presence of single versus multiple mutations did not affect optimal PCR responses. At a median follow-up of 53.1 months, the median relapse-free survival (RFS) for the whole cohort was 27.7 months (range, 1.7-93.6). RAS-mutated pts had longer RFS than non-mutated pts (not reached vs. 43.78 months, p=0.02); however, KIT mutation did not affect RFS. Additionally, the number of the RAS or KIT mutations did not impact RFS.
    CONCLUSIONS: KIT mutation might negatively affect the attainment of optimal PCR responses at the end of FLAG-based therapy but lacks significant impacts on RFS. Single versus multiple KIT or RAS mutations do not appear to impact therapy response.
    Keywords:  AML; C-KIT; RAS; core-binding factor
    DOI:  https://doi.org/10.1016/S2152-2650(22)01265-4
  58. iScience. 2022 Oct 21. 25(10): 104931
    A machine learning model of response to hypomethylating agents in myelodysplastic syndromes.
    Nathan Radakovich, David A Sallman, Rena Buckstein, Andrew Brunner, Amy Dezern, Sudipto Mukerjee, Rami Komrokji, Najla Al-Ali, Jacob Shreve, Yazan Rouphail, Anne Parmentier, Alexandre Mamedov, Mohammed Siddiqui, Yihong Guan, Teodora Kuzmanovic, Metis Hasipek, Babal Jha, Jaroslaw P Maciejewski, Mikkael A Sekeres, Aziz Nazha.
      Hypomethylating agents (HMA) prolong survival and improve cytopenias in individuals with higher-risk myelodysplastic syndrome (MDS). Only 30-40% of patients, however, respond to HMAs, and responses may not occur for more than 6 months after HMA initiation. We developed a model to more rapidly assess HMA response by analyzing early changes in patients' blood counts. Three institutions' data were used to develop a model that assessed patients' response to therapy 90 days after the initiation using serial blood counts. The model was developed with a training cohort of 424 patients from 2 institutions and validated on an independent cohort of 90 patients. The final model achieved an area under the receiver operating characteristic curve (AUROC) of 0.79 in the train/test group and 0.84 in the validation group. The model provides cohort-wide and individual-level explanations for model predictions, and model certainty can be interrogated to gauge the reliability of a given prediction.
    Keywords:  Drugs; artificial intelligence; cancer
    DOI:  https://doi.org/10.1016/j.isci.2022.104931
  59. Clin Lymphoma Myeloma Leuk. 2022 Oct;pii: S2152-2650(22)01254-X. [Epub ahead of print]22 Suppl 2 S229-S230
    AML-251 Overall Survival (OS) With Intensive Chemotherapy (IC) vs Non-IC in Patients With Newly Diagnosed (ND) AML from the Connect® Myeloid Disease Registry Ineligible for Randomized Clinical Trials (RCT).
    Harry P Erba, Daniel A Pollyea, Mikkael A Sekeres, Guillermo Garcia-Manero, Karen Seiter, Irene S DeGutis, Pavel Kiselev, Ali McBride, Edward Yu, Gail J Roboz.
       CONTEXT: Patients with acute myeloid leukemia (AML) in RCTs may not reflect the population seen in clinical practice due to strict eligibility criteria.
    OBJECTIVE: To evaluate outcomes in clinical practice with IC vs venetoclax-containing regimens based on the VIALE-A trial eligibility criteria in patients with AML from the Connect® Myeloid Disease Registry (NCT01688011).
    DESIGN: Patients were stratified into 3 groups: 1) eligible: met all VIALE-A inclusion criteria; 2) unfit: ineligible for VIALE-A; 3) fit: ineligible for a venetoclax-based regimen in VIALE-A (would have qualified for IC). Baseline characteristics were summarized by group. Induction regimens included IC or venetoclax-based therapies.
    MAIN OUTCOME MEASURES: OS was estimated by Kaplan-Meier method. Hazard ratios (HR) for induction regimens were estimated using Cox models adjusted for age, ELN risk, ECOG, frailty score, and comorbidity index.
    RESULTS: Of 734 patients (Dec 2021), 61% were male; 84% were white; median age 71 years. Only 26% of patients (n=192) were eligible for VIALE-A; 45% (n=327) and 29% (n=215) were ineligible due to unfitness and overall fitness, respectively. The main reason for VIALE-A ineligibility was high overall comorbidity grade (n=265 [36%]). At baseline, fit patients intended to undergo transplant more often than unfit patients. Median OS (mOS) for eligible, unfit, and fit patients was 14, 10, and 22 months, respectively (HR [95%CI], eligible vs unfit, 1.02 [0.83-1.25], P-value, NS; eligible vs fit, 1.77 [1.38-2.25], P<0.0001; unfit vs fit, 1.74 [1.40-2.16], P<0.0001). Unfit patients receiving IC had significantly longer mOS (14 vs 6 months, respectively; HR, 0.51 [95%CI, 0.27-0.98]; P=0.042) and were more likely to receive a transplant (16% [n=17] vs 1% [n=1], respectively) vs those receiving venetoclax-based regimens. Eligible patients receiving IC (n=31) tended to have shorter mOS (13 months) vs patients receiving venetoclax-based therapies (n=27; 23 months; HR, 1.45 [95%CI, 0.66-3.17]; P-value, NS).
    CONCLUSIONS: Most patients with ND AML in the Connect® Myeloid Disease Registry would have been ineligible for VIALE-A due to being too fit or unfit. Among patients ineligible for an RCT due to unfitness, there was an association with increased OS in patients receiving IC vs those receiving venetoclax-based therapies.
    Keywords:  AML; acute myeloid leukemia; chemotherapy; eligibility criteria; overall survival; registry
    DOI:  https://doi.org/10.1016/S2152-2650(22)01254-X
  60. Cancer Cell. 2022 Sep 19. pii: S1535-6108(22)00436-6. [Epub ahead of print]
    Inhibition of the CtBP complex and FBXO11 enhances MHC class II expression and anti-cancer immune responses.
    Kah Lok Chan, Juliana Gomez, Chelisa Cardinez, Nishi Kumari, Christina E Sparbier, Enid Y N Lam, Miriam M Yeung, Sylvain Garciaz, James A Kuzich, Doen Ming Ong, Fiona C Brown, Yih-Chih Chan, Dane Vassiliadis, Elanor N Wainwright, Ali Motazedian, Andrea Gillespie, Katie A Fennell, Junyun Lai, Imran G House, Laura Macpherson, Ching-Seng Ang, Sarah-Jane Dawson, Paul A Beavis, Andrew H Wei, Marian L Burr, Mark A Dawson.
      There is increasing recognition of the prognostic significance of tumor cell major histocompatibility complex (MHC) class II expression in anti-cancer immunity. Relapse of acute myeloid leukemia (AML) following allogeneic stem cell transplantation (alloSCT) has recently been linked to MHC class II silencing in leukemic blasts; however, the regulation of MHC class II expression remains incompletely understood. Utilizing unbiased CRISPR-Cas9 screens, we identify that the C-terminal binding protein (CtBP) complex transcriptionally represses MHC class II pathway genes, while the E3 ubiquitin ligase complex component FBXO11 mediates degradation of CIITA, the principal transcription factor regulating MHC class II expression. Targeting these repressive mechanisms selectively induces MHC class II upregulation across a range of AML cell lines. Functionally, MHC class II+ leukemic blasts stimulate antigen-dependent CD4+ T cell activation and potent anti-tumor immune responses, providing fundamental insights into the graft-versus-leukemia effect. These findings establish the rationale for therapeutic strategies aimed at restoring tumor-specific MHC class II expression to salvage AML relapse post-alloSCT and also potentially to enhance immunotherapy outcomes in non-myeloid malignancies.
    Keywords:  CtBP; FBXO11; MHC class II; acute myeloid leukemia; bone marrow transplantation; cancer epigenetics; gene regulation; melanoma; tumor immunology
    DOI:  https://doi.org/10.1016/j.ccell.2022.09.007
  61. Blood Adv. 2022 Sep 26. pii: bloodadvances.2022008481. [Epub ahead of print]
    RNA-Regulatory Exosome Complex Suppresses an Apoptotic Program to Confer Erythroid Progenitor Cell Survival In Vivo.
    Isabela Fraga de Andrade, Kirby D Johnson, Charu Mehta, Colin Dewey, Uttiya Basu, Emery H Bresnick.
      The RNA exosome complex (EC) post-transcriptionally and co-transcriptionally processes and degrades RNAs in a context-dependent manner. Although the EC functions in diverse cell types, its contributions to stem and progenitor cell development are not well understood. Previously, we demonstrated that the transcriptional regulator of erythrocyte development GATA1 represses EC subunit genes, and the EC maintains erythroid progenitors in vitro. To determine if this mechanism operates in vivo, we utilized the hematopoietic-specific Vav1-Cre and "Conditional Inversion" (Coin = C) mouse system to ablate Exosc3, encoding an EC structural subunit. Although Exosc3C/C Cre+ embryos developed normally until E14.5, Exosc3 ablation was embryonic lethal and severely reduced erythro-myeloid progenitor activity. RNA-seq analysis of Exosc3-ablated BFU-E revealed elevated transcripts encoding multiple pro-apoptotic factors, and the mutant erythroid progenitors exhibited increased apoptosis. We propose that the EC controls an ensemble of apoptosis-regulatory RNAs, thereby promoting erythroid progenitor survival and developmental erythropoiesis in vivo.
    DOI:  https://doi.org/10.1182/bloodadvances.2022008481
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