Patel, Prapti A.

Abstract Abstract text: Background/Introduction: Chronic Myelomonocytic Leukemia (CMML) is an uncommon MDS/MPN overlap syndrome that has historically been included under the umbrella of myelodysplastic syndromes (MDS) for clinical trial and treatment. As a result, DNA methyltransferase inhibitors (DNMTi) such as decitabine or azacitidine have been the established standard of care for the treatment of CMML. The oral bioavailability of these agents has been limited due to rapid degradation by cytidine deaminase (CDA) in the gut and liver so treatment has required intravenous infusion or subcutaneous injections daily for 5-7 days every month (m) adding significant burden to older cancer patients due to daily time commitment and travel to treatment centers. In the context of pandemic SARS-CoV-2, parenteral therapy also increases contact with medical settings with increased infection risk. Oral decitabine 35 mg/cedazuridine 100 mg (ASTX727) is an oral fixed dose combination of decitabine and the CDA inhibitor cedazuridine that produced equivalent exposure (99%; 90% CI 93% to 106%) to IV decitabine 20 mg/m 2 in a randomized cross-over study (Garcia-Manero et al, ASH 2019), and Median overall survival (mOS) for the entire study population in the ASCERTAIN study was approximately 32 months (Savona, 2021). Here, we present outcome data for this study for the enrolled subpopulation of patients with CMML. Methods: We used a randomized cross over design in which patients were randomized in the first 2 cycles 1:1 to either Sequence A: (decitabine 35 mg/ cedazuridine 100 mg in Cycle 1 followed by IV decitabine at 20 mg/m 2 in Cycle 2), or Sequence B: (IV decitabine in Cycle 1 followed by oral decitabine/cedazuridine in Cycle 2). We conducted an intra-patient comparison of decitabine PK (primary PK endpoint: decitabine AUC equivalence over 5 days of dosing). Cycles were repeated every 28 days (unless delays were needed). All patients received oral decitabine/cedazuridine in Cycles 3 and above until disease progression or unacceptable toxicity. Patients were eligible per the FDA-approved label of IV decitabine (MDS patients by FAB classification including CMML, or MDS IPSS Intermediate-1, 2 or high-risk patients). Clinical endpoints were best response according to International Working Group (IWG) 2006 response criteria, transfusion independence for at least 8 or 16 consecutive weeks, overall survival, and safety. Adverse events (AEs) were graded by Common Terminology Criteria for Adverse Events (CTCAE) v 4.03. Results: Of the 133 patients enrolled and treated in ASCERTAIN, 16 (12%) had a diagnosis of CMML with demographics and as follows: median age 71.5 years, 69% Male/31% Female, median weight 87kg (range 65-124), 25% ECOG 0, 75% ECOG 1. Population disease characteristics were: 19% poor or intermediate risk cytogenetics, with median baseline hemoglobin 90 g/L, neutrophils 1.27 X 10 9/L, platelets 84 x 10 9/L, bone marrow blasts 5%, with 38% RBC transfusion dependent. Patients received a median of 7 cycles of therapy (range 3-24). Treatment-emergent adverse events of CTCAE Grade 3 or higher in > 10% of patients, independent of relationship to ASTX727, were cytopenias (neutropenia [69%], thrombocytopenia [63%], anemia [56%], leukopenia [19%]), febrile neutropenia (31%), fatigue (13%). Two patients (12.5%) had Complete Responses (CR), 8 (50%) had marrow CR ([mCR], including 3 (19%) with hematologic improvement (HI); Overall Response rate (ORR) [CR + PR+ mCR + HI] was 75%. Of six patients with baseline RBC transfusion dependence 3 (50%) became transfusion independent. Leukemia-free survival was 28.2 months and after a median follow up of more than 33 months, median overall survival had not been reached. Two patients (13%) went on to Hematopoietic Stem Cell Transplant (HCT). Conclusions: In the overall study, oral decitabine/cedazuridine delivered equivalent PK exposure to 5 days of IV decitabine 20mg/m 2 with a resultant clinical activity safety and efficacy profile in CMML patients consistent with the published literature (e.g Zeidan, et al 2017) and the Phase 2 experience. The use of oral decitabine/cedazuridine is a reasonable approach in CMML patients. References: Garcia-Manero, et al ASH 2019 Savona, et al, Int. MDS Symposium, 2021 Zeidan, et al, Cancer 2017: 3754-3762. Figure 1 Figure 1. Disclosures Savona: Geron: Consultancy, Membership on an entity's Board of Directors or advisory committees; CTI: Consultancy, Membership on an entity's Board of Directors or advisory committees; Karyopharm: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; BMS-Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; NOVARTIS: Consultancy, Membership on an entity's Board of Directors or advisory committees; Ryvu: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sierra Oncology: Consultancy, Membership on an entity's Board of Directors or advisory committees; Taiho: Consultancy, Membership on an entity's Board of Directors or advisory committees; TG Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; ALX Oncology: Research Funding; Astex: Research Funding; Incyte: Research Funding. McCloskey: Pfizer: Consultancy; Takeda: Consultancy, Speakers Bureau; Incyte: Speakers Bureau; Novartis: Consultancy; COTA: Other: Equity Ownership; BMS: Honoraria, Speakers Bureau; Amgen: Speakers Bureau; Jazz: Consultancy, Speakers Bureau. Griffiths: Boston Biomedical: Consultancy; Celgene/Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Honoraria; Taiho Oncology: Consultancy, Honoraria; Genentech: Research Funding; Astex Pharmaceuticals: Honoraria, Research Funding; Takeda Oncology: Consultancy, Honoraria; Novartis: Honoraria; Apellis Pharmaceuticals: Research Funding; Alexion Pharmaceuticals: Consultancy, Research Funding. Yee: Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Forma Therapeutics: Research Funding; Geron: Research Funding; Shattuck Labs: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb/Celgene: Membership on an entity's Board of Directors or advisory committees; F. Hoffmann La Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Honoraria; Janssen: Research Funding; Onconova: Research Funding; Genentech: Research Funding; Otsuka: Membership on an entity's Board of Directors or advisory committees; MedImmune: Research Funding; Jazz: Research Funding; Astex: Membership on an entity's Board of Directors or advisory committees, Research Funding; Tolero: Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees; TaiHo: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Paladin: Membership on an entity's Board of Directors or advisory committees. Zeidan: BeyondSpring: Consultancy; Janssen: Consultancy; Boehringer Ingelheim: Consultancy, Research Funding; BioCryst: Other: Clinical Trial Committees; AstraZeneca: Consultancy; Pfizer: Other: Travel support, Research Funding; Kura: Consultancy, Other: Clinical Trial Committees; Incyte: Consultancy, Research Funding; Ionis: Consultancy; Daiichi Sankyo: Consultancy; Epizyme: Consultancy; Novartis: Consultancy, Other: Clinical Trial Committees, Travel support, Research Funding; Loxo Oncology: Consultancy, Other: Clinical Trial Committees; Genentech: Consultancy; Geron: Other: Clinical Trial Committees; Cardiff Oncology: Consultancy, Other: Travel support, Research Funding; BMS: Consultancy, Other: Clinical Trial Committees, Research Funding; Gilead: Consultancy, Other: Clinical Trial Committees; Aprea: Consultancy, Research Funding; Astellas: Consultancy; Astex: Research Funding; Jazz: Consultancy; Jasper: Consultancy; Amgen: Consultancy, Research Funding; Agios: Consultancy; ADC Therapeutics: Research Funding; Acceleron: Consultancy, Research Funding; AbbVie: Consultancy, Other: Clinical Trial Committees, Research Funding. Al-Kali: Novartis: Research Funding; Astex: Other: Research support to institution. Patel: Agios: Membership on an entity's Board of Directors or advisory committees; Celgene-BMS: Membership on an entity's Board of Directors or advisory committees; PVI: Honoraria. Sabloff: Takeda: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; TaiHo: Membership on an entity's Board of Directors or advisory committees; Jaxx: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; ROCHE: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Dao: Astex Pharmaceuticals, Inc.: Current Employment. Fazal: Janssen Oncology: Consultancy, Honoraria, Speakers Bureau; Taiho Pharmaceuticals: Consultancy, Honoraria, Speakers Bureau; Gilead Sciences: Consultancy, Honoraria, Speakers Bureau; Novartis: Consultancy, Honoraria, Speakers Bureau; Agios: Consultancy, Honoraria, Speakers Bureau; Sanofi Genzyme: Consultancy, Honoraria, Speakers Bureau; Takeda: Consultancy, Honoraria, Speakers Bureau; Glaxo Smith Kline: Consultancy, Honoraria, Speakers Bureau; AMGEN: Consultancy, Honoraria, Speakers Bureau; Incyte: Consultancy, Honoraria, Speakers Bureau; Jazz Pharmaceuticals: Consultancy, Honoraria, Speakers Bureau; Bristol Myers Squibb: Consultancy, Honoraria, Speakers Bureau; Stemline Therapeutics: Consultancy, Honoraria, Speakers Bureau; Karyopharm Pharmaceuticals: Consultancy, Honoraria, Speakers Bureau. Odenike: Celgene, Incyte, AstraZeneca, Astex, NS Pharma, AbbVie, Gilead, Janssen, Oncotherapy, Agios, CTI/Baxalta, Aprea: Research Funding; AbbVie, Celgene, Impact Biomedicines, Novartis, Taiho Oncology, Takeda: Consultancy. Kantarjian: Ipsen Pharmaceuticals: Honoraria; Astra Zeneca: Honoraria; Astellas Health: Honoraria; Aptitude Health: Honoraria; Pfizer: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Jazz: Research Funding; Immunogen: Research Funding; Daiichi-Sankyo: Research Funding; BMS: Research Funding; Ascentage: Research Funding; Amgen: Honoraria, Research Funding; AbbVie: Honoraria, Research Funding; KAHR Medical Ltd: Honoraria; NOVA Research: Honoraria; Precision Biosciences: Honoraria; Taiho Pharmaceutical Canada: Honoraria. DeZern: Bristol-Myers Squibb: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Taiho: Consultancy, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees. Roboz: Janssen: Research Funding; AbbVie: Consultancy; Actinium: Consultancy; Agios: Consultancy; Amgen: Consultancy; Astex: Consultancy; Astellas: Consultancy; AstraZeneca: Consultancy; Bayer: Consultancy; Blueprint Medicines: Consultancy; Bristol Myers Squibb: Consultancy; Celgene: Consultancy; Daiichi Sankyo: Consultancy; Glaxo SmithKline: Consultancy; Helsinn: Consultancy; Janssen: Consultancy; Jasper Therapeutics: Consultancy; Jazz: Consultancy; MEI Pharma - IDMC Chair: Consultancy; Mesoblast: Consultancy; Novartis: Consultancy; Otsuka: Consultancy; Pfizer: Consultancy; Roche/Genentech: Consultancy. Busque: Novartis: Consultancy. Leber: Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AMGEN: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; TaiHo: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Otsuka: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Astellas: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Jazz: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Hao: Astex Pharmaceuticals, Inc.: Current Employment. Keer: Astex Pharmaceuticals, Inc.: Current Employment. Azab: Astex Pharmaceuticals, Inc.: Membership on an entity's Board of Directors or advisory committees.

Abstract Background: GILT is an oral potent selective FLT3 kinase inhibitor approved for marketing for the treatment (Tx) of patients (pts) with relapsed/refractory FLT3 mutated (FLT3m) AML but efficacy in older ND FLT3m AML pts is unknown. Furthermore, FLT3m can be present as a dominant or subclone and impact of FLT3 inhibitor therapy in this setting is uncertain. Here we report the results of a Phase 2/1b sub-study of the Beat AML Master Trial to assess the efficacy of GILT monotherapy (GILTm) in ND FLT3m AML pts aged ≥60 years with high and low VAF and the subsequent response-driven addition of DEC Tx. (ClinicalTrials.gov NCT03013998) Methods: The study was an open-label multicenter (15 sites), 3-outcome, 2-stage Phase 2 design that assigned pts to either Dominant FLT3/Group 1 (GP1) or Non-Dominant FLT3/Group 2 (GP2) as shown in Figure 1. Key eligibility criteria included ND FLT3m AML pts with high and low VAF and/or ITD ratio, aged ≥60 years, and ECOG performance status 0-2. In the Phase 2 study, all pts received GILTm 120 mg/day on days 1 - 28. Pts without CR/CRi after cycle 2 were transferred to the Phase 1b study to receive GILT + DEC (Figure 1). Phase 1b study utilized a standard 3+3 design to evaluate the safety/tolerability of concurrent GILT + DEC. Pts received GILT (dose level 1 [DL1] = 80 mg/day or dose level 2 [DL2] = 120 mg/day on days 1-28) + DEC 20 mg/m 2 IV on days 1-10 or 1-5 every 28 days. Primary endpoint was CR+CRi rate (Phase 2). Response was assessed using modified 2017 ELN AML criteria. The non-dominant GP2 was stopped for futility, GP1 was stopped early to modify trial to include venetoclax. Results: Phase 2 - Between 9/10/2018 to 2/11/2020, 19 / 20 enrolled pts (GP1: n = 9; GP2: n = 10) received GILTm and were included in analyses. Baseline pt characteristics are shown in Table 1. Median (range) time on GILTm was 3 cycles (1 - 18) in GP1 and 1 cycle (1 - 9) in GP2. Most common reasons for discontinuing Tx were Tx failure (TF; 44%) and relapse (33%) in GP1 and TF (70%) and disease progression (PD; 20%) in GP2. Overall CR+CRi was achieved in 4 pts (44%) in GP1 and 1 pt (10%) in GP2. Response duration are shown in Table 2. After median follow-up of 14.3 months (mos) and 19 mos in GP1 and GP2, respectively, 1-year OS was 56% and 76%. Most common Grade ≥3 adverse events (AEs) were febrile neutropenia and colitis (each 25%) in GP1; anemia and low platelet count in GP2 (each 30%). Overall, 7 pts had 15 serious AEs (SAEs) and all SAEs occurred in GP1 pts; most common SAE was colitis (25%) and 1 pt (13%) had a Tx-related Grade 3 SAE of tumor lysis syndrome. In GP2, 1 pt (10%) had Tx-related Grade 2 AE of differentiation syndrome. In GP1, 2 pts died within 60 days of Tx and none in GP2. Phase1b - After up to 2 cycles of GILTm, 12 pts with no CR/CRi (GP1: n = 4; GP2: n = 8) were transferred to receive GILT + DEC (Figure 1). At the time of this report, 1 pt with CRh remained on Tx. Median total time on Tx (including GILTm) was 4 cycles and median time on GILT + DEC Tx was 3 cycles (Table 2). Most common reasons for discontinuing Tx were PD (33%) and TF (25%); and 2 pts (17%) stopped Tx due to an AE. Pts were treated with DL1 GILT + DEC (n = 3), then DL2 GILT + DEC (n = 9); only 1 pt had dose-limiting toxicity (DLT) at DL2 (Grade 3 hyperbilirubinemia and pneumonitis requiring steroid therapy), hence, DL2 GILT + DEC was considered the MTD. CR+CRi rate was 25% in 3 pts, all at DL2 (Table 2). After a median follow-up of 17.8 mos, the 1-year OS from start of GILT + DEC Tx was 57%. Most common Grade ≥3 Tx-related AEs were anemia, febrile neutropenia and low WBC count (each 22%). Overall, 6 pts had 12 SAEs; 1 pt with SAE of Grade 4 sepsis died. Three GILT-related SAEs occurred in 1 pt - Grade 3 hyperbilirubinemia, and pneumonitis and Grade 1 transaminases increased. One pt died within 30 days and a second within 60 days of Tx. No difference was observed in GILT pharmacokinetics (PK) with or without DEC, however steady state Ctrough values were 1.4 to 2.3-fold greater than in relapsed/refractory AML pts (Admiral trial). Conclusions: In ND pts ≥60 years old with dominant FLT3 AML, GILTm induced a high 44% CR+CRi rate and long median OS (21.7 mos). Pts with non-dominant FLT3 had low 10% CR+CRi rate. GILTm was generally safe and was associated with differentiation syndrome in 1 pt. Concurrent GILT + DEC was acceptably tolerated, only 1 pt had a DLT, and the MTD was 120 mg/day GILT + DEC. A subset of pts with no CR/CRi during GILTm achieved remission with addition of DEC. Based on these results, a triple combination Tx study with venetoclax is currently enrolling. Figure 1 Figure 1. Disclosures Traer: Genentech: Membership on an entity's Board of Directors or advisory committees; Schrodinger: Research Funding; Incyte: Research Funding; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Servier/Agios: Membership on an entity's Board of Directors or advisory committees; Astellas: Consultancy, Membership on an entity's Board of Directors or advisory committees; ImmunoGen: Membership on an entity's Board of Directors or advisory committees. Mims: Glycomemetics: Research Funding; Daiichi Sankyo: Consultancy, Research Funding; Aptevo: Research Funding; Leukemia and Lymphoma Society's Beat AML clinical study: Consultancy, Research Funding; Genentech: Consultancy; Xencor: Research Funding; Kartos Pharmaceuticals: Research Funding; Abbvie: Consultancy; BMS: Consultancy; Kura Oncology: Consultancy; Syndax Pharmaceuticals: Consultancy; BMS: Consultancy; Jazz Pharmaceuticals: Consultancy; Aptevo: Research Funding. Stein: Agios Pharmaceuticals, Inc: Consultancy; Novartis: Consultancy; Astellas: Consultancy; Syndax Pharmaceuticals: Consultancy; Daiichi Sankyo: Consultancy; Syros Pharmaceuticals, Inc.: Consultancy; PinotBio: Consultancy; Celgene: Consultancy; Bristol Myers Squibb: Consultancy; Jazz Pharmaceuticals: Consultancy; Foghorn Therapeutics: Consultancy; Blueprint Medicines: Consultancy; Gilead Sciences, Inc.: Consultancy; Abbvie: Consultancy; Janssen Pharmaceuticals: Consultancy; Genentech: Consultancy. Stock: Pfizer: Consultancy, Honoraria, Research Funding; amgen: Honoraria; agios: Honoraria; jazz: Honoraria; kura: Honoraria; kite: Honoraria; morphosys: Honoraria; servier: Honoraria; syndax: Consultancy, Honoraria; Pluristeem: Consultancy, Honoraria. Kovacsovics: AbbVie: Research Funding; Jazz Pharmaceutials: Honoraria; Janssen Pharmaceuticals: Research Funding; Amgen Inc.: Research Funding; Stemline: Honoraria; Novartis: Research Funding. Blum: Xencor: Research Funding; Abbvie: Honoraria; Nkarta: Research Funding; Celyad Oncology: Research Funding; AmerisourceBergen: Honoraria; Forma Therapeutics: Research Funding; Leukemia and Lymphoma Society: Research Funding; Syndax: Honoraria. Arellano: Syndax Pharmaceuticals, Inc: Consultancy; KITE Pharma, Inc: Consultancy. Schiller: Actinium Pharmaceuticals, Inc: Research Funding; Mateon: Research Funding; Tolero: Research Funding; Geron: Research Funding; Regimmune: Research Funding; Kite/Gilead: Honoraria, Research Funding, Speakers Bureau; Celator: Research Funding; Sangamo: Research Funding; Stemline Therapeutics, Inc.: Honoraria, Research Funding, Speakers Bureau; Takeda: Research Funding; PrECOG: Research Funding; Pfizer: Current equity holder in publicly-traded company, Research Funding; Karyopharm: Research Funding; Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Gamida Cell Ltd.: Research Funding; FujiFilm: Research Funding; Samus: Research Funding; Trovagene: Research Funding; Daiichi-Sankyo: Research Funding; Constellation Pharmaceuticals: Research Funding; BMS/Celgene: Consultancy, Current equity holder in publicly-traded company, Research Funding, Speakers Bureau; Abbvie: Research Funding; Actuate: Research Funding; Arog: Research Funding; Delta-Fly: Research Funding; Amgen: Consultancy, Current equity holder in publicly-traded company, Honoraria, Research Funding, Speakers Bureau; Agios: Consultancy, Research Funding, Speakers Bureau; Novartis: Consultancy, Research Funding; Jazz: Consultancy, Honoraria, Research Funding, Speakers Bureau; Elevate: Research Funding; Ono-UK: Consultancy, Research Funding; Onconova: Research Funding; Deciphera: Research Funding; Astellas: Honoraria, Research Funding, Speakers Bureau; Forma: Research Funding; Genentech-Roche: Research Funding; Bio: Research Funding; Sanofi: Honoraria, Research Funding, Speakers Bureau; Pharma: Consultancy; Johnson & Johnson: Current equity holder in publicly-traded company; Biomed Valley Discoveries: Research Funding; Eli Lilly: Research Funding; ASH foundation: Other: Chair-unpaid; Sellas: Research Funding; Ono: Consultancy; Incyte: Consultancy; Ariad: Research Funding; AstraZeneca: Consultancy; Kaiser Permanente: Consultancy; Cyclacel: Research Funding; MedImmune: Research Funding; Ambit: Research Funding; Leukemia & Lymphoma Society: Research Funding; Bluebird Bio: Research Funding; Boehringer-Ingleheim: Research Funding; Cellerant: Research Funding; CTI Biopharma: Research Funding; Janssen: Research Funding; Kura Oncology: Research Funding; Pharmacyclics: Honoraria, Speakers Bureau; Millennium: Research Funding; National Marrow Donor Program: Research Funding; NIH: Research Funding; Onyx: Research Funding; Pharmamar: Research Funding; UC Davis: Research Funding; UCSD: Research Funding; Evidera: Consultancy; NCI: Consultancy; Novartis: Speakers Bureau. Olin: Astellas: Honoraria, Research Funding; Daiichi Sankyo: Research Funding; Genentech: Research Funding; Pfizer: Research Funding; Cellectis: Research Funding; Amgen: Honoraria; Abbvie: Honoraria; Actinium: Honoraria. Foran: taiho: Honoraria; syros: Honoraria; kura: Research Funding; boehringer ingelheim: Research Funding; sanofi aventis: Honoraria; trillium: Research Funding; aptose: Research Funding; abbvie: Research Funding; pfizer: Honoraria; gamida: Honoraria; actinium: Research Funding; takeda: Research Funding; certara: Honoraria; OncLive: Honoraria; bms: Honoraria; revolution medicine: Honoraria; servier: Honoraria; novartis: Honoraria; h3bioscience: Research Funding; aprea: Research Funding; sellas: Research Funding; stemline: Research Funding. Litzow: AbbVie: Research Funding; Jazz: Other: Advisory Board; Pluristem: Research Funding; Amgen: Research Funding; Omeros: Other: Advisory Board; Actinium: Research Funding; Astellas: Research Funding; Biosight: Other: Data monitoring committee. Lin: AbbVie, Aptevo Therapeutics, Astellas Pharma, Bio-Path Holdings, Celgene, Celyad, Genentech-Roche, Gilead Sciences, Incyte, Jazz Pharmaceuticals, Novartis, Ono Pharmaceutical, Pfizer, Prescient Therapeutics, Seattle Genetics, Tolero, Trovagene: Research Funding. Patel: BMS-Celgene, Agios: Membership on an entity's Board of Directors or advisory committees; Peerview: Honoraria; Aptevo Therapeutics: Research Funding. Foster: Bellicum Pharmaceuticals: Research Funding; Macrogenics: Research Funding; Rafael Pharmaceuticals: Research Funding; Macrogenics: Consultancy; Daiichi Sankyo: Consultancy; Agios: Consultancy. Cogle: Aptevo therapeutics: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees. Vergilio: Foundation Medicine: Current Employment. Gana: The Leukemia & Lymphoma Society: Consultancy; Bausch: Current holder of individual stocks in a privately-held company. Druker: VB Therapeutics: Membership on an entity's Board of Directors or advisory committees; The RUNX1 Research Program: Membership on an entity's Board of Directors or advisory committees; GRAIL: Current equity holder in publicly-traded company; Third Coast Therapeutics: Membership on an entity's Board of Directors or advisory committees; EnLiven: Consultancy, Research Funding; Iterion Therapeutics: Membership on an entity's Board of Directors or advisory committees; Recludix Pharma, Inc.: Consultancy; Pfizer: Research Funding; Merck & Co: Patents & Royalties; Cepheid: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Patents & Royalties; Nemucore Medical Innovations, Inc.: Consultancy; Bristol-Myers Squibb: Research Funding; Blueprint Medicines: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Aptose Therapeutics: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Amgen: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; ALLCRON: Consultancy, Membership on an entity's Board of Directors or advisory committees; Aileron: Membership on an entity's Board of Directors or advisory committees; Vincerx Pharma: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Vivid Biosciences: Membership on an entity's Board of Directors or advisory committees. Byrd: Novartis, Trillium, Astellas, AstraZeneca, Pharmacyclics, Syndax: Consultancy, Honoraria; Vincerx Pharmaceuticals: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Newave: Membership on an entity's Board of Directors or advisory committees. Levine: Auron: Membership on an entity's Board of Directors or advisory committees; Incyte: Consultancy; Ajax: Membership on an entity's Board of Directors or advisory committees; C4 Therapeutics: Membership on an entity's Board of Directors or advisory committees; Isoplexis: Membership on an entity's Board of Directors or advisory committees; Astellas: Consultancy; Celgene: Research Funding; Roche: Honoraria, Research Funding; Zentalis: Membership on an entity's Board of Directors or advisory committees; Prelude: Membership on an entity's Board of Directors or advisory committees; Mission Bio: Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria; Janssen: Consultancy; Gilead: Honoraria; Morphosys: Consultancy; Imago: Membership on an entity's Board of Directors or advisory committees; QIAGEN: Membership on an entity's Board of Directors or advisory committees; Lilly: Honoraria. Borate: Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding; Blueprint Medicine: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: Membership on an entity's Board of Directors or advisory committees, Other: Advisory Board; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding; Jazz Pharma: Research Funding; Daiichi-Sankyo: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees; incyte: Membership on an entity's Board of Directors or advisory committees, Research Funding; Rampal: Membership on an entity's Board of Directors or advisory committees; Galecto, Inc.: Consultancy; Promedior: Consultancy.

Abstract Background: In vitro studies and emerging clinical data suggest that inhibition of spleen tyrosine kinase may have an antileukemic effect in human AML. Pts with AML and TP53 mutations (TP53m) are commonly associated with older age (≥60 years) and complex karyotype (CK) and respond poorly to standard 7 + 3 induction (IND) chemotherapy with <10% 1-year overall survival (OS). DEC has been reported to improve response in TP53m AML. Here, we report the results of a Phase 2 sub-study of the Beat AML Master Trial that assessed the efficacy of ENTO + DEC combination treatment (Tx) in ND AML patients (pts) with TP53m or CK aged ≥60 years. [ClinicalTrials.gov: NCT03013998] Methods: This multicenter (13 sites), open-label, Phase 2 combination Tx study utilized Simon's 2-stage Phase 2 design and enrolled AML pts with TP53m (identified molecularly) ± CK (Cohort A) or CK (≥3 metaphase abnormalities) without TP53m (Cohort B). Pts initially received 5 days of ENTO lead-in (which was later discontinued), followed by ENTO + DEC and those who achieved CR/CRh/CRi/MLFS with up to 3 cycles of IND proceeded to consolidation (CON) Tx for up to 11 cycles (Figure 1). Pts with CRi/MLFS after IND were allowed up to 6 cycles (IND + CON) to achieve CR/CRh or stayed on Tx if they got clinical benefit or went off Tx. CON was followed by maintenance (MTN) Tx for up to 2 years from start of study Tx. Pts were eligible if aged ≥60 years, ND, and had ECOG performance status 0 - 2. Pts received ENTO 400 mg orally twice daily for 5 days during ENTO lead-in, and then every 28 days during IND, CON, and MTN + DEC 20 mg/m 2 IV days 1-10 (IND) or days 1-5 (CON) every 28 days. Response was assessed using modified 2017 ELN AML criteria. The primary endpoint was composite complete remission (CCR) rate (CR + CRh) with up to 3 cycles of IND, and CRi/MLFS that achieved CR/CRh by up to 6 cycles (IND + CON). Beyond stage 1, pt accrual to Cohort A was allowed based on pts with CRi and to Cohort B was stopped early for futility. Results: Between Oct 2017 and Feb 2020, of the 63 pts enrolled (Cohort A = 48; Cohort B = 15), pts with confirmed eligibility who started study Tx were included in the analyses (Cohort A = 45; Cohort B = 13). During lead-in, 27 pts in Cohort A and 6 pts in Cohort B received ENTOm for 5 days. All pts received ENTO + DEC except 1 pt in Cohort A who withdrew consent (WOC). Median ages of the pts were 70 years (range 60 - 84) in Cohort A and 74 years (range 65 - 86) in Cohort B. Median time (range) on Tx was 2.2 mos and 4.8 mos in Cohort A and B, respectively. Most common reasons for Tx discontinuation were adverse event (AE; 27%), Tx failure (TF; 27%) and WOC (18%) in Cohort A; TF (31%), disease progression and relapse (each 15%) in Cohort B. In each cohort, 1 pt discontinued Tx due to death from leukemia and 1 pt in Cohort A in CRh due to development of an additional genetic abnormality. Four pts (9%) in Cohort A and 1 pt (8%) in Cohort B proceeded to transplant. The CCR (CR + CRh) rates with up to 6 cycles of Tx for Cohort A and B were 13.3% and 30.8%, respectively; overall CR + CRh rates were 17.8% and 38.5% (Table 1). In Cohort A, with a median follow-up of 11.5 months, 0% were 1-year disease-free and median OS (mOS) was 6.5 months. In Cohort B, with a median follow-up of 15.1 months, 25% were 1-year disease-free and mOS was 11.5 months. Deaths within 7-, 30-, and 60-days of Tx were 0, 3 and 11 in Cohort A and 0, 0 and 2 in Cohort B. Most common treatment-related Grade ≥3 AEs in Cohort A and B were febrile neutropenia (31% and 39%) and anemia (22% and 31%) (Table 2). Overall, 83 serious AEs (SAEs) were reported in 33 pts in Cohort A and 12 SAEs in 6 pts in Cohort B; most common SAEs in Cohort A were pneumonia (18%) and respiratory failure (11%), and in Cohort B sepsis, dehydration and acute kidney injury (each 15%). Most common treatment-related grade ≥3 laboratory abnormalities in Cohort A and B were neutrophils decreased (27% and 31%), WBC count decreased (20% and 23%), and lymphocyte count decreased (18% and 15%). Conclusions: ENTO + DEC demonstrated activity in ND AML pts aged ≥60 years with TP53m ± CK and CK without TP53 but induced low CR/CRh rates and short OS consistent with previously published poor CR rates and OS in these pts. Our results differ from the high remission rate and longer OS previously reported for DEC monotherapy in AML pts with TP53m. ENTO + DEC was safe and acceptably tolerated. Novel Tx strategies that can benefit AML pts with these most adverse risk factors are urgently needed. Figure 1 Figure 1. Disclosures Ruppert: Telios Pharma: Consultancy. Mims: Leukemia and Lymphoma Society's Beat AML clinical study: Consultancy, Research Funding; Aptevo: Research Funding; Daiichi Sankyo: Consultancy, Research Funding; Glycomemetics: Research Funding; Kartos Pharmaceuticals: Research Funding; Xencor: Research Funding; Genentech: Consultancy; Abbvie: Consultancy; BMS: Consultancy; Kura Oncology: Consultancy; Syndax Pharmaceuticals: Consultancy; BMS: Consultancy; Jazz Pharmaceuticals: Consultancy; Aptevo: Research Funding. Borate: Jazz Pharma: Research Funding; Daiichi-Sankyo: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Blueprint Medicine: Membership on an entity's Board of Directors or advisory committees; Genentech: Membership on an entity's Board of Directors or advisory committees, Other: Advisory Board; Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding; Astellas: Membership on an entity's Board of Directors or advisory committees; incyte: Membership on an entity's Board of Directors or advisory committees, Research Funding; Rampal: Membership on an entity's Board of Directors or advisory committees; Galecto, Inc.: Consultancy; Promedior: Consultancy. Stein: Abbvie: Consultancy; Janssen Pharmaceuticals: Consultancy; Gilead Sciences, Inc.: Consultancy; Foghorn Therapeutics: Consultancy; Syros Pharmaceuticals, Inc.: Consultancy; Daiichi Sankyo: Consultancy; Blueprint Medicines: Consultancy; PinotBio: Consultancy; Genentech: Consultancy; Jazz Pharmaceuticals: Consultancy; Bristol Myers Squibb: Consultancy; Celgene: Consultancy; Agios Pharmaceuticals, Inc: Consultancy; Novartis: Consultancy; Astellas: Consultancy; Syndax Pharmaceuticals: Consultancy. Stock: Pfizer: Consultancy, Honoraria, Research Funding; amgen: Honoraria; agios: Honoraria; jazz: Honoraria; kura: Honoraria; kite: Honoraria; morphosys: Honoraria; servier: Honoraria; syndax: Consultancy, Honoraria; Pluristeem: Consultancy, Honoraria. Kovacsovics: AbbVie: Research Funding; Janssen Pharmaceuticals: Research Funding; Amgen Inc.: Research Funding; Novartis: Research Funding; Stemline: Honoraria; Jazz Pharmaceutials: Honoraria. Blum: Amerisource Bergen; Abbvie, Syndax: Honoraria; Forma Therapeutics, Xencor; Celyad: Research Funding. Arellano: KITE Pharma, Inc: Consultancy; Syndax Pharmaceuticals, Inc: Consultancy. Schiller: Actinium Pharmaceuticals, Inc: Research Funding; Gamida Cell Ltd.: Research Funding; Pfizer: Current equity holder in publicly-traded company, Research Funding; Forma: Research Funding; Agios: Consultancy, Research Funding, Speakers Bureau; Constellation Pharmaceuticals: Research Funding; MedImmune: Research Funding; Ambit: Research Funding; Karyopharm: Research Funding; Daiichi-Sankyo: Research Funding; Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Kaiser Permanente: Consultancy; Abbvie: Research Funding; AstraZeneca: Consultancy; Genentech-Roche: Research Funding; Delta-Fly: Research Funding; Cyclacel: Research Funding; Mateon: Research Funding; Actuate: Research Funding; Onconova: Research Funding; Geron: Research Funding; Sangamo: Research Funding; Arog: Research Funding; Ariad: Research Funding; Stemline Therapeutics, Inc.: Honoraria, Research Funding, Speakers Bureau; Takeda: Research Funding; Trovagene: Research Funding; Ono-UK: Consultancy, Research Funding; Tolero: Research Funding; BMS/Celgene: Consultancy, Current equity holder in publicly-traded company, Research Funding, Speakers Bureau; Celator: Research Funding; Kite/Gilead: Honoraria, Research Funding, Speakers Bureau; Astellas: Honoraria, Research Funding, Speakers Bureau; Incyte: Consultancy; Novartis: Consultancy, Research Funding; Deciphera: Research Funding; FujiFilm: Research Funding; Samus: Research Funding; Regimmune: Research Funding; PrECOG: Research Funding; Amgen: Consultancy, Current equity holder in publicly-traded company, Honoraria, Research Funding, Speakers Bureau; Bio: Research Funding; Elevate: Research Funding; Jazz: Consultancy, Honoraria, Research Funding, Speakers Bureau; Biomed Valley Discoveries: Research Funding; Ono: Consultancy; Eli Lilly: Research Funding; Sellas: Research Funding; ASH foundation: Other: Chair-unpaid; Leukemia & Lymphoma Society: Research Funding; Bluebird Bio: Research Funding; Sanofi: Honoraria, Research Funding, Speakers Bureau; Pharma: Consultancy; Johnson & Johnson: Current equity holder in publicly-traded company; Boehringer-Ingleheim: Research Funding; Cellerant: Research Funding; CTI Biopharma: Research Funding; Janssen: Research Funding; Kura Oncology: Research Funding; Pharmacyclics: Honoraria, Speakers Bureau; Millennium: Research Funding; National Marrow Donor Program: Research Funding; NIH: Research Funding; Onyx: Research Funding; Pharmamar: Research Funding; UC Davis: Research Funding; UCSD: Research Funding; Evidera: Consultancy; NCI: Consultancy; Novartis: Speakers Bureau. Olin: Astellas: Honoraria, Research Funding; Actinium: Honoraria; Amgen: Honoraria; Abbvie: Honoraria; Cellectis: Research Funding; Daiichi Sankyo: Research Funding; Genentech: Research Funding; Pfizer: Research Funding. Foran: certara: Honoraria; pfizer: Honoraria; syros: Honoraria; taiho: Honoraria; boehringer ingelheim: Research Funding; servier: Honoraria; revolution medicine: Honoraria; trillium: Research Funding; takeda: Research Funding; abbvie: Research Funding; novartis: Honoraria; bms: Honoraria; OncLive: Honoraria; gamida: Honoraria; sanofi aventis: Honoraria; aptose: Research Funding; actinium: Research Funding; kura: Research Funding; h3bioscience: Research Funding; aprea: Research Funding; sellas: Research Funding; stemline: Research Funding. Litzow: AbbVie: Research Funding; Omeros: Other: Advisory Board; Astellas: Research Funding; Pluristem: Research Funding; Jazz: Other: Advisory Board; Actinium: Research Funding; Amgen: Research Funding; Biosight: Other: Data monitoring committee. Lin: AbbVie, Aptevo Therapeutics, Astellas Pharma, Bio-Path Holdings, Celgene, Celyad, Genentech-Roche, Gilead Sciences, Incyte, Jazz Pharmaceuticals, Novartis, Ono Pharmaceutical, Pfizer, Prescient Therapeutics, Seattle Genetics, Tolero, Trovagene: Research Funding. Cogle: Aptevo therapeutics: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees. Vergilio: Foundation Medicine: Current Employment; Roche: Current equity holder in publicly-traded company. Gana: Bausch: Current holder of individual stocks in a privately-held company; The Leukemia & Lymphoma Society: Consultancy. Druker: The RUNX1 Research Program: Membership on an entity's Board of Directors or advisory committees; Aileron: Membership on an entity's Board of Directors or advisory committees; Novartis Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Patents & Royalties; Recludix Pharma, Inc.: Consultancy; Third Coast Therapeutics: Membership on an entity's Board of Directors or advisory committees; Vincerx Pharma: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; VB Therapeutics: Membership on an entity's Board of Directors or advisory committees; GRAIL: Current equity holder in publicly-traded company; Iterion Therapeutics: Membership on an entity's Board of Directors or advisory committees; ALLCRON: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Aptose Therapeutics: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Blueprint Medicines: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Research Funding; EnLiven: Consultancy, Research Funding; Merck & Co: Patents & Royalties; Pfizer: Research Funding; Nemucore Medical Innovations, Inc.: Consultancy; Cepheid: Consultancy, Membership on an entity's Board of Directors or advisory committees; Vivid Biosciences: Membership on an entity's Board of Directors or advisory committees. Byrd: Vincerx Pharmaceuticals: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Novartis, Trillium, Astellas, AstraZeneca, Pharmacyclics, Syndax: Consultancy, Honoraria; Newave: Membership on an entity's Board of Directors or advisory committees. Levine: Isoplexis: Membership on an entity's Board of Directors or advisory committees; Gilead: Honoraria; Zentalis: Membership on an entity's Board of Directors or advisory committees; Imago: Membership on an entity's Board of Directors or advisory committees; Ajax: Membership on an entity's Board of Directors or advisory committees; Lilly: Honoraria; Prelude: Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria; Janssen: Consultancy; Celgene: Research Funding; Roche: Honoraria, Research Funding; Auron: Membership on an entity's Board of Directors or advisory committees; C4 Therapeutics: Membership on an entity's Board of Directors or advisory committees; Incyte: Consultancy; Astellas: Consultancy; Morphosys: Consultancy; QIAGEN: Membership on an entity's Board of Directors or advisory committees; Mission Bio: Membership on an entity's Board of Directors or advisory committees. OffLabel Disclosure: Off-label use of entospletinib and decitabine.

Abstract Background: IVO is an oral potent inhibitor of mutated IDH1 (IDH1m) enzyme, recently approved for the treatment (Tx) of ND adult patients (pts) with IDH1m AML ≥75 years old or with comorbidities precluding use of intensive induction chemotherapy, and adult pts with relapsed or refractory AML. In this Phase 2 sub-study of the Beat AML Master Trial, we evaluated the efficacy of IVO + AZA combination Tx in ND pts aged ≥60 years with IDH1m AML (ClinicalTrials.gov: NCT03013998) Methods: This open-label multicenter (16 sites / 9 enrolling) combination Tx study enrolled ND pts with R132 mIDH1 AML, utilizing the modified minimax Simon's 2-stage Phase 2 design. Pts received IVO + AZA for 6 cycles in the absence of disease progression (PD), unacceptable toxicity or stem cell transplant. Pts who achieved complete remission (CR)/complete remission with hematologic improvement (CRh)/complete remission with incomplete hematologic recovery (CRi) continued IVO + AZA for a total of 12 cycles, then IVO monotherapy until PD. Pts without CR/CRh/CRi after 6 cycles continued IVO + AZA if they demonstrated Tx benefit, as defined in Figure 1. Key eligibility included ND IDH1 R132 mutated AML pts aged ≥60 years and ECOG performance status 0 - 2 (Karnofsky ≥60). All pts received IVO 500 mg/day orally in continuous 28-day cycles + AZA 75 mg/m2 IV or SC on days 1-7 every 28 days. The primary endpoint was CR+CRh+CRi rate after 6 cycles of Tx. Response was assessed using modified 2017 ELN AML criteria. The modified minimax Simon's 2-stage design required 40 pts and tested the null hypothesis that the CR/CRh/CRi rate equaled 25% vs the alternative of 50% (one-sided alpha = 0.025, power 90%). Stage 1 required >5/16 responses for continued enrollment. Even though these criteria were met, the sponsor decided to discontinue the trial on 12/12/2019. Here we report the final primary endpoint results. Data were frozen 02/03/2021. Results: Between 07/2018 and 11/2019, 19 patients were enrolled with IDH1m AML; 18 started IVO + AZA Tx and are included in the analyses. At data freeze, 5 pts had died and 7 pts still on Tx were offered standard of care IVO. Median age of the pts was 75 years, 50% were ≥75 years, 61% were female and 89% were White (Table 1). The most common reasons for Tx discontinuation were trial discontinued by sponsor (7 or 39%), stem cell transplant (4 or 22%), and PD (3 or 17%). A total of 13 pts achieved CR/CRh/CRi (72%) by up to 6 cycles of Tx (Table 2 & Figure 2). Over the entire study period, 14 pts achieved CR/CRh/CRi (78%) with 8 CR (44%), 3 CRh (17%) and 3 CRi (17%). No deaths occurred within the first 60 days of Tx. After a median follow up of 19.8 months (mos), Page 2 median response duration was not reached, with 12-mos disease-free survival rate of 69%; also, median OS was not reached, with 12- and 18-mos OS rates of 100% and 73%, respectively. The median (range) time on Tx was 12 mos (<1 - 26.6); 2 pts (11%) discontinued Tx due to an adverse event (AE) - 2 Grade 3 serious AEs (SAEs), differentiation syndrome and skin infection. Overall, 5 pts had 7 Tx-related SAEs; most common Tx-related SAE was differentiation syndrome in 4 pts (22%), of which 3 (17%) were considered Grade ≥3 (Table 3). The most common AEs of any grade (in ≥25% of pts) were diarrhea (61%), constipation (50%), nausea and hypokalemia (each 44%); and most common Grade ≥3 Tx-related AEs were differentiation syndrome and QTc prolongation (each 17%). The most common Tx-related laboratory abnormalities of any grade were decreased platelet count (22%) and decreased WBC count (17%). Conclusions: In ND pts with IDH1m AML and ≥60 years of age, IVO + AZA Tx was associated with a high CR/CRh/CRi rate, no early deaths (60 days) and a 1-year OS of 100%. IVO + AZA was acceptably tolerated and no unexpected toxicities occurred. Most common unique toxicities of IVO observed during the study were differentiation syndrome and QTc prolongation; these led to Tx discontinuation in only 1 pt. CR/CRh/CRi rate obtained with IVO +AZA is higher than that previously reported in studies with the individual agents or intensive chemotherapy approaches, suggesting a synergistic effect. Our overall response rate is similar to that reported recently for IVO + AZA in older ND IDH1 mutant AML pts, despite not including pts with morphologic leukemia-free state and partial remission. Based on these results, a global Phase 3 evaluation of IVO or placebo plus AZA is ongoing (NCT03173248). Figure 1 Figure 1. Disclosures Patel: BMS-Celgene, Agios: Membership on an entity's Board of Directors or advisory committees; Aptevo Therapeutics: Research Funding; Peerview: Honoraria. Ruppert: Telios Pharma: Consultancy. Borate: Daiichi-Sankyo: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees; Genentech: Membership on an entity's Board of Directors or advisory committees, Other: Advisory Board; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Jazz Pharma: Research Funding; Blueprint Medicine: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees; incyte: Membership on an entity's Board of Directors or advisory committees, Research Funding; Rampal: Membership on an entity's Board of Directors or advisory committees; Galecto, Inc.: Consultancy; Promedior: Consultancy. Stein: Syros Pharmaceuticals, Inc.: Consultancy; Daiichi Sankyo: Consultancy; PinotBio: Consultancy; Celgene: Consultancy; Bristol Myers Squibb: Consultancy; Jazz Pharmaceuticals: Consultancy; Foghorn Therapeutics: Consultancy; Blueprint Medicines: Consultancy; Gilead Sciences, Inc.: Consultancy; Abbvie: Consultancy; Janssen Pharmaceuticals: Consultancy; Genentech: Consultancy; Agios Pharmaceuticals, Inc: Consultancy; Novartis: Consultancy; Astellas: Consultancy; Syndax Pharmaceuticals: Consultancy. Stock: Pfizer: Consultancy, Honoraria, Research Funding; amgen: Honoraria; agios: Honoraria; jazz: Honoraria; kura: Honoraria; kite: Honoraria; morphosys: Honoraria; servier: Honoraria; syndax: Consultancy, Honoraria; Pluristeem: Consultancy, Honoraria. Kovacsovics: AbbVie: Research Funding; Janssen Pharmaceuticals: Research Funding; Amgen Inc.: Research Funding; Novartis: Research Funding; Stemline: Honoraria; Jazz Pharmaceutials: Honoraria. Blum: Leukemia and Lymphoma Society: Research Funding; Nkarta: Research Funding; Celyad Oncology: Research Funding; Syndax: Honoraria; Xencor: Research Funding; Abbvie: Honoraria; Forma Therapeutics: Research Funding; AmerisourceBergen: Honoraria. Arellano: KITE Pharma, Inc: Consultancy; Syndax Pharmaceuticals, Inc: Consultancy. Schiller: Sangamo: Research Funding; Takeda: Research Funding; Ono-UK: Consultancy, Research Funding; Gamida Cell Ltd.: Research Funding; Tolero: Research Funding; Samus: Research Funding; Karyopharm: Research Funding; BMS/Celgene: Consultancy, Current equity holder in publicly-traded company, Research Funding, Speakers Bureau; Amgen: Consultancy, Current equity holder in publicly-traded company, Honoraria, Research Funding, Speakers Bureau; Bio: Research Funding; Mateon: Research Funding; Genentech-Roche: Research Funding; FujiFilm: Research Funding; Agios: Consultancy, Research Funding, Speakers Bureau; Actinium Pharmaceuticals, Inc: Research Funding; Kite/Gilead: Honoraria, Research Funding, Speakers Bureau; Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Arog: Research Funding; Delta-Fly: Research Funding; Celator: Research Funding; Forma: Research Funding; Astellas: Honoraria, Research Funding, Speakers Bureau; Stemline Therapeutics, Inc.: Honoraria, Research Funding, Speakers Bureau; Regimmune: Research Funding; PrECOG: Research Funding; Constellation Pharmaceuticals: Research Funding; Trovagene: Research Funding; Elevate: Research Funding; Deciphera: Research Funding; Actuate: Research Funding; Jazz: Consultancy, Honoraria, Research Funding, Speakers Bureau; Daiichi-Sankyo: Research Funding; Onconova: Research Funding; Geron: Research Funding; Novartis: Consultancy, Research Funding; Pfizer: Current equity holder in publicly-traded company, Research Funding; Abbvie: Research Funding; Sanofi: Honoraria, Research Funding, Speakers Bureau; Pharma: Consultancy; Johnson & Johnson: Current equity holder in publicly-traded company; Biomed Valley Discoveries: Research Funding; Eli Lilly: Research Funding; ASH foundation: Other: Chair-unpaid; Sellas: Research Funding; Ono: Consultancy; Incyte: Consultancy; Ariad: Research Funding; AstraZeneca: Consultancy; Kaiser Permanente: Consultancy; Cyclacel: Research Funding; MedImmune: Research Funding; Ambit: Research Funding; Leukemia & Lymphoma Society: Research Funding; Bluebird Bio: Research Funding; Boehringer-Ingleheim: Research Funding; Cellerant: Research Funding; CTI Biopharma: Research Funding; Janssen: Research Funding; Kura Oncology: Research Funding; Pharmacyclics: Honoraria, Speakers Bureau; Millennium: Research Funding; National Marrow Donor Program: Research Funding; NIH: Research Funding; Onyx: Research Funding; Pharmamar: Research Funding; UC Davis: Research Funding; UCSD: Research Funding; Evidera: Consultancy; NCI: Consultancy; Novartis: Speakers Bureau. Olin: Actinium: Honoraria; Abbvie: Honoraria; Amgen: Honoraria; Cellectis: Research Funding; Pfizer: Research Funding; Genentech: Research Funding; Daiichi Sankyo: Research Funding; Astellas: Honoraria, Research Funding. Foran: pfizer: Honoraria; gamida: Honoraria; servier: Honoraria; kura: Research Funding; abbvie: Research Funding; takeda: Research Funding; trillium: Research Funding; revolution medicine: Honoraria; novartis: Honoraria; certara: Honoraria; sanofi aventis: Honoraria; bms: Honoraria; syros: Honoraria; taiho: Honoraria; OncLive: Honoraria; actinium: Research Funding; aptose: Research Funding; boehringer ingelheim: Research Funding; h3bioscience: Research Funding; aprea: Research Funding; sellas: Research Funding; stemline: Research Funding. Litzow: Pluristem: Research Funding; Astellas: Research Funding; AbbVie: Research Funding; Jazz: Other: Advisory Board; Amgen: Research Funding; Actinium: Research Funding; Omeros: Other: Advisory Board; Biosight: Other: Data monitoring committee. Lin: AbbVie, Aptevo Therapeutics, Astellas Pharma, Bio-Path Holdings, Celgene, Celyad, Genentech-Roche, Gilead Sciences, Incyte, Jazz Pharmaceuticals, Novartis, Ono Pharmaceutical, Pfizer, Prescient Therapeutics, Seattle Genetics, Tolero, Trovagene: Research Funding. Foster: Agios: Consultancy; Daiichi Sankyo: Consultancy; Macrogenics: Consultancy; Rafael Pharmaceuticals: Research Funding; Macrogenics: Research Funding; Bellicum Pharmaceuticals: Research Funding. Cogle: Celgene: Membership on an entity's Board of Directors or advisory committees; Aptevo therapeutics: Research Funding. Vergilio: Roche: Current equity holder in publicly-traded company; Foundation Medicine: Current Employment. Gana: Bausch: Current holder of individual stocks in a privately-held company; The Leukemia & Lymphoma Society: Consultancy. Druker: The RUNX1 Research Program: Membership on an entity's Board of Directors or advisory committees; EnLiven: Consultancy, Research Funding; Amgen: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Aptose Therapeutics: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Blueprint Medicines: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; GRAIL: Current equity holder in publicly-traded company; Nemucore Medical Innovations, Inc.: Consultancy; Merck & Co: Patents & Royalties; Novartis Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Patents & Royalties; Bristol-Myers Squibb: Research Funding; Cepheid: Consultancy, Membership on an entity's Board of Directors or advisory committees; Iterion Therapeutics: Membership on an entity's Board of Directors or advisory committees; Recludix Pharma, Inc.: Consultancy; Third Coast Therapeutics: Membership on an entity's Board of Directors or advisory committees; VB Therapeutics: Membership on an entity's Board of Directors or advisory committees; Aileron: Membership on an entity's Board of Directors or advisory committees; ALLCRON: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pfizer: Research Funding; Vincerx Pharma: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Vivid Biosciences: Membership on an entity's Board of Directors or advisory committees. Byrd: Vincerx Pharmaceuticals: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Novartis, Trillium, Astellas, AstraZeneca, Pharmacyclics, Syndax: Consultancy, Honoraria; Newave: Membership on an entity's Board of Directors or advisory committees. Levine: QIAGEN: Membership on an entity's Board of Directors or advisory committees; Imago: Membership on an entity's Board of Directors or advisory committees; Ajax: Membership on an entity's Board of Directors or advisory committees; Mission Bio: Membership on an entity's Board of Directors or advisory committees; Zentalis: Membership on an entity's Board of Directors or advisory committees; Lilly: Honoraria; Celgene: Research Funding; Isoplexis: Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Research Funding; Incyte: Consultancy; Janssen: Consultancy; Astellas: Consultancy; Morphosys: Consultancy; Gilead: Honoraria; Amgen: Honoraria; C4 Therapeutics: Membership on an entity's Board of Directors or advisory committees; Prelude: Membership on an entity's Board of Directors or advisory committees; Auron: Membership on an entity's Board of Directors or advisory committees. Mims: Leukemia and Lymphoma Society: Consultancy; Kura Oncology: Consultancy; Genentech: Consultancy; Abbvie: Consultancy; Syndax Pharmaceuticals: Consultancy; BMS: Consultancy; Aptevo: Research Funding; Xencor: Research Funding; Glycomemetics: Research Funding; Jazz Pharmaceuticals: Consultancy; Daiichi-Saynko: Consultancy. OffLabel Disclosure: IVO is an oral potent inhibitor of mutated IDH1 enzyme, recently approved for the treatment of ND adult patients with IDH1m AML âââ,¬Â°Ã,Â¥75 years old or with comorbidities precluding use of intensive induction chemotherapy, and adult pts with relapsed or refractory AML. The combination of AZA, a hypomethylating agent, and venetoclax, an oral BCL-2 inhibitor, is also FDA approved for newly diagnosed AML in adults 75 years or older, or who have comorbidities precluding intensive chemotherapy. This presentation will discuss the combination of IVO and AZA.

Abstract Background/Introduction: Lower-risk (IPSS low risk and Int-1) myelodysplastic syndromes (MDS) are typically treated supportively to address cytopenias. DNA methyltransferase inhibitors (DNMTi) such as azacitidine and decitabine (DEC) are FDA-approved for higher risk MDS patients (pts), and while the DEC USPI includes IPSS Int-1 pts, it is not widely used in this population. Approved intravenous (IV) or subcutaneous (SC) regimens require 5-7 days of treatment every month burdening older cancer pts due to daily travel and treatment time and may increase potential risk from pandemic SARS-CoV-2 infection. Because DNMTis are rapidly degraded by cytidine deaminase (CDA) in the gut and liver, oral availability has only been recently possible. A randomized study with CC-486, an oral formulation of azacitidine, in the Int-1 population showed a median overall survival (mOS) of approximately 17 months for both placebo and treated patients (Garcia-Manero, 2021). Oral DEC 35 mg/cedazuridine 100 mg (ASTX727) or DEC-C, is an oral fixed dose combination (FDC) of DEC and the CDA inhibitor cedazuridine (CED) resulting in equivalent exposure (99%; 90% CI 93% to 106%) to standard IV DEC 20 mg/m 2 for 5 days in an intra-patient randomized cross-over study (Garcia-Manero et al, ASH 2019). Here, we present data on patients with lower risk MDS from that study. Methods: We used a randomized cross over design with pts randomized 1:1 in the first 2 cycles to either Sequence A: (DEC 35 mg/ CED 100 mg in Cycle 1 and IV DEC at 20 mg/m 2 in Cycle 2), or Sequence B (IV DEC in Cycle 1 and oral DEC/CED in Cycle 2). Cycles were repeated every 28 days unless delays were needed, and all patients received oral DEC-C in Cycles 3+ until disease progression or unacceptable toxicity. We conducted an intra-patient comparison of DEC PK (DEC AUC equivalence over 5 days of dosing). Pts were eligible as per the FDA-approved label of IV DEC (MDS pts by FAB classification including CMML, or MDS IPSS Intermediate-1, 2 or high-risk pts). Clinical endpoints were best response as assessed by an independent expert panel according to IWG 2006 response criteria, transfusion independence (TI), overall survival (OS), and safety. Results: Of the 133 pts treated in ASCERTAIN, 69 had a diagnosis of lower-risk MDS (93% Int-1, 7% LR). Median age was 70.0 years (range 45-87), 65% were male, median weight was 84 kg (range 50-127), median baseline hematologic parameters were: hemoglobin 89 g/L (range 69.8-146.5), WBCs 1.50 X 10 9/L (range 0.11-7.1), platelets (plt) 86 x 10 9/L (range 5-703), bone marrow blasts 4% (range 0-18), cytogenetics: 7 (10.1%) poor-risk, 21 (30.4%) intermediate risk, 37 (53.6%) better-risk, 4 (5.7%) missing or not evaluable. 27(39%) of the pts were RBC transfusion dependent (TD) and 6 (9%) plt TD. 17 (25%) had received prior MDS treatment, 3% prior DNMTi. Pts received a median of 9 cycles of therapy (range 1-28). Treatment-emergent adverse events of CTCAE Gr 3 or higher in >10% of pts, independent of relationship to ASTX727, included cytopenias (neutropenia [59%], thrombocytopenia [58%], anemia [48%], leukopenia [26%]), febrile neutropenia (32%), and pneumonia (19%). Sixteen pts (23%) achieved Complete Response (CR), 18 (26%) had marrow CR (mCR), including 9 (13%) with hematologic improvement (HI). Overall Response rate (ORR; CR + PR+ mCR + HI) was 57%. Of those RBC or plt TD at baseline, 13 (48%) became RBC TI and 4 (67%) became plt TI. With approximately 32 months of median follow up, neither median leukemia-free survival (mLFS) nor mOS had been reached (Figure 1). Twelve pts (17%) went on to allogeneic stem cell transplant. Conclusions: Oral decitabine/cedazuridine given as a FDC in MDS pts produced equivalent PK exposure to 20 mg/m 2 IV DEC; in lower risk MDS pts with treatment indicated, the agent was generally well-tolerated with prolonged treatment and could result in mLFS and mOS which exceeds 32 months. This FDC and other dosing regimens of oral DEC-C should be further studied in this patient population. References: Garcia-Manero, et al, ASH 2019 Savona, et al, Int. MDS Symp. 2021 Garcia-Manero, et al, Phase III, Randomized, Placebo-Controlled Trial of CC-486 (Oral Azacitidine) in Patients with Lower-Risk Myelodysplastic Syndromes. J.Clin.Onc. 2021 39:13, 1426-1436 Figure 1 Figure 1. Disclosures McCloskey: Pfizer: Consultancy; Jazz: Consultancy, Speakers Bureau; COTA: Other: Equity Ownership; Incyte: Speakers Bureau; Takeda: Consultancy, Speakers Bureau; Novartis: Consultancy; BMS: Honoraria, Speakers Bureau; Amgen: Speakers Bureau. Griffiths: Alexion Pharmaceuticals: Consultancy, Research Funding; Abbvie: Consultancy, Honoraria; Taiho Oncology: Consultancy, Honoraria; Genentech: Research Funding; Novartis: Honoraria; Takeda Oncology: Consultancy, Honoraria; Astex Pharmaceuticals: Honoraria, Research Funding; Celgene/Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding; Apellis Pharmaceuticals: Research Funding; Boston Biomedical: Consultancy. Yee: Paladin: Membership on an entity's Board of Directors or advisory committees; TaiHo: Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: Research Funding; Geron: Research Funding; Janssen: Research Funding; Jazz: Research Funding; MedImmune: Research Funding; Onconova: Research Funding; Tolero: Research Funding; AbbVie: Honoraria; Bristol-Myers Squibb/Celgene: Membership on an entity's Board of Directors or advisory committees; Otsuka: Membership on an entity's Board of Directors or advisory committees; Shattuck Labs: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; F. Hoffmann La Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding; Forma Therapeutics: Research Funding; Astex: Membership on an entity's Board of Directors or advisory committees, Research Funding. Zeidan: Novartis: Consultancy, Other: Clinical Trial Committees, Travel support, Research Funding; Genentech: Consultancy; Ionis: Consultancy; Astellas: Consultancy; Epizyme: Consultancy; AbbVie: Consultancy, Other: Clinical Trial Committees, Research Funding; Jasper: Consultancy; Cardiff Oncology: Consultancy, Other: Travel support, Research Funding; BeyondSpring: Consultancy; Loxo Oncology: Consultancy, Other: Clinical Trial Committees; Janssen: Consultancy; Acceleron: Consultancy, Research Funding; AstraZeneca: Consultancy; Kura: Consultancy, Other: Clinical Trial Committees; Gilead: Consultancy, Other: Clinical Trial Committees; Agios: Consultancy; Daiichi Sankyo: Consultancy; Boehringer Ingelheim: Consultancy, Research Funding; Geron: Other: Clinical Trial Committees; BMS: Consultancy, Other: Clinical Trial Committees, Research Funding; BioCryst: Other: Clinical Trial Committees; Pfizer: Other: Travel support, Research Funding; Aprea: Consultancy, Research Funding; ADC Therapeutics: Research Funding; Jazz: Consultancy; Incyte: Consultancy, Research Funding; Amgen: Consultancy, Research Funding; Astex: Research Funding. Al-Kali: Astex: Other: Research support to institution; Novartis: Research Funding. Patel: Celgene-BMS: Membership on an entity's Board of Directors or advisory committees; PVI: Honoraria; Agios: Membership on an entity's Board of Directors or advisory committees. Sabloff: Pfizer: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; ROCHE: Membership on an entity's Board of Directors or advisory committees; TaiHo: Membership on an entity's Board of Directors or advisory committees; Jaxx: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees. Dao: Astex Pharmaceuticals, Inc.: Current Employment. Fazal: Taiho Pharmaceuticals: Consultancy, Honoraria, Speakers Bureau; Stemline Therapeutics: Consultancy, Honoraria, Speakers Bureau; Sanofi Genzyme: Consultancy, Honoraria, Speakers Bureau; Novartis: Consultancy, Honoraria, Speakers Bureau; Karyopharm Pharmaceuticals: Consultancy, Honoraria, Speakers Bureau; Jazz Pharmaceuticals: Consultancy, Honoraria, Speakers Bureau; Janssen Oncology: Consultancy, Honoraria, Speakers Bureau; Incyte: Consultancy, Honoraria, Speakers Bureau; Glaxo Smith Kline: Consultancy, Honoraria, Speakers Bureau; Gilead Sciences: Consultancy, Honoraria, Speakers Bureau; Bristol Myers Squibb: Consultancy, Honoraria, Speakers Bureau; AMGEN: Consultancy, Honoraria, Speakers Bureau; Agios: Consultancy, Honoraria, Speakers Bureau; Takeda: Consultancy, Honoraria, Speakers Bureau. Odenike: AbbVie, Celgene, Impact Biomedicines, Novartis, Taiho Oncology, Takeda: Consultancy; Celgene, Incyte, AstraZeneca, Astex, NS Pharma, AbbVie, Gilead, Janssen, Oncotherapy, Agios, CTI/Baxalta, Aprea: Research Funding. Kantarjian: AbbVie: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Ascentage: Research Funding; Pfizer: Honoraria, Research Funding; BMS: Research Funding; Daiichi-Sankyo: Research Funding; Amgen: Honoraria, Research Funding; Ipsen Pharmaceuticals: Honoraria; Jazz: Research Funding; Astellas Health: Honoraria; Immunogen: Research Funding; Astra Zeneca: Honoraria; Aptitude Health: Honoraria; KAHR Medical Ltd: Honoraria; NOVA Research: Honoraria; Precision Biosciences: Honoraria; Taiho Pharmaceutical Canada: Honoraria. DeZern: Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Taiho: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Consultancy, Membership on an entity's Board of Directors or advisory committees. Roboz: Novartis: Consultancy; Mesoblast: Consultancy; Jasper Therapeutics: Consultancy; Jazz: Consultancy; MEI Pharma - IDMC Chair: Consultancy; Daiichi Sankyo: Consultancy; Otsuka: Consultancy; Bristol Myers Squibb: Consultancy; Blueprint Medicines: Consultancy; Bayer: Consultancy; AstraZeneca: Consultancy; Astellas: Consultancy; Astex: Consultancy; Amgen: Consultancy; Agios: Consultancy; Actinium: Consultancy; AbbVie: Consultancy; Janssen: Research Funding; Celgene: Consultancy; Glaxo SmithKline: Consultancy; Helsinn: Consultancy; Janssen: Consultancy; Pfizer: Consultancy; Roche/Genentech: Consultancy. Busque: Novartis: Consultancy. Leber: Astellas: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Otsuka: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; TaiHo: Honoraria, Membership on an entity's Board of Directors or advisory committees; AMGEN: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Jazz: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Hao: Astex Pharmaceuticals, Inc.: Current Employment. Keer: Astex Pharmaceuticals, Inc.: Current Employment. Azab: Astex Pharmaceuticals, Inc.: Membership on an entity's Board of Directors or advisory committees. Savona: Geron: Consultancy, Membership on an entity's Board of Directors or advisory committees; Karyopharm: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; CTI: Consultancy, Membership on an entity's Board of Directors or advisory committees; BMS-Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; NOVARTIS: Consultancy, Membership on an entity's Board of Directors or advisory committees; Ryvu: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sierra Oncology: Consultancy, Membership on an entity's Board of Directors or advisory committees; Taiho: Consultancy, Membership on an entity's Board of Directors or advisory committees; TG Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; ALX Oncology: Research Funding; Astex: Research Funding; Incyte: Research Funding.

Background: ENA is an oral, selective inhibitor of IDH2 approved for the treatment (Tx) of patients (pts) with relapsed/refractory IDH2 mutated (IDH2m) AML. Here we report the results of a Phase 2 expansion and Phase 1b of the Beat AML Master Trial Phase 2/1b sub-study to assess the efficacy of Tx of newly diagnosed (ND) IDH2m AML pts ≥ 60 years of age with ENA monotherapy (ENAm) and subsequent response-driven addition of AZA Tx. (ClinicalTrials.gov NCT03013998). Methods: The study initiated with a 3-outcome, 2-stage Phase 2 design, which enrolled patients on ENAm for up to 5 cycles. Pts without CR/CRi after 5 cycles of ENAm, or progression/intolerance prior to this time, were transferred to Phase 1b to receive ENA + AZA (Figure 1). Key eligibility included ND IDH2m AML pts with age ≥ 60 years and ECOG performance status 0-2. Pts received ENAm 100 mg/day in continuous 28-day cycles and ENA + AZA (75 mg/m2 days 1-7 every 28 days) for Phase 1b. Response was assessed using 2017 ELN AML criteria. The primary endpoint was CR/CRi rate. The 2-stage design required 24 pts and tested the null hypothesis (H0) that CR/CRi rate equaled 20% vs 50% and then expanded to test a revised H0 of 30% vs 50% in 60 pts (conditional alpha=0.025, power=77%). Expansion also allowed further assessment of safety of this treatment regimen. Results: At data cut off (06/18/2020), 60 pts enrolled, received ENAm, and were evaluable for the primary endpoint. Median age was 75 years and 52% were female (Table 1). Median time on ENAm was 4.7 months (mos). At data cut off, 12 pts were still on ENAm Tx. Most common reasons for discontinuing ENAm were Tx failure (defined as no response to treatment) (23 or 38%), disease progression (loss of response to treatment) (7 or 12%) and adverse events (AEs; 6 or 10%). Five pts (8%) went to transplant. CR/CRi was achieved in 28 pts (47%; adjusted 95% CI 28-59, unadjusted exact 95% CI 34-60) (Table 2). Responses were higher (p=0.04) among the 44 pts with IDH2 R140 (55%) as compared to the 16 with IDH2 R172 mutation (25%) further supporting distinct biology between these subsets. After a median follow up of 14.6 mos, the median overall survival (mOS) was 24.4 mos (95% CI 10.6-not reached). The median duration of response was not reached with 12 mos estimation of 57% (95% CI 34-75). Overall, 20 ENA-related serious adverse events (SAEs) occurred in 15 pts, the most common was differentiation syndrome (12 or 20%) and 1 had ENA-related SAE of tumor lysis syndrome (1.7%). One pt had ENA-related Grade 5 AE (renal failure/death). Most common AEs of any grade (in ≥20%) were nausea, anemia, and low potassium (Table 3). The 7-day/30-day/60-day deaths observed with ENAm were 2%/5%/11%, respectively. Phase 1b: Seventeen pts had inadequate response to ENAm and transferred to Phase 1b to receive ENA + AZA. Median time on Tx (including ENAm) was 6.2 mos and median time on Tx after pts started ENA + AZA was 2.1 mos (Table 2). Most common reasons for discontinuing ENA + AZA included Tx failure (5 or 29%), disease progression (2 or 12%), transplant, death and AEs (each 2 or 12%). CR/CRi was 41% (exact 95% CI 18-67). After a median follow up of 12.7 mos, the mOS from start of ENA + AZA combination Tx was 8.9 mos. Four ENA-related SAEs occurred in 3 pts on ENA + AZA Tx and the most common was differentiation syndrome (2 or 12.5%). One dose-limiting toxicity (Grade 3 nausea) related to both Txs was observed. Most common AEs (≥20%) of any grade were anemia, low albumin and vomiting (Table 3). One death occurred at day 13 of ENA + AZA. Conclusions: In newly diagnosed pts ≥60 years old with IDH2m AML, ENA had a low early death rate, high CR/CRi rate (47%, adjusted 95% CI 28-59), and yielded durable remissions. The most common unique toxicity with ENA was differentiation syndrome that occurred in 20% of patients. In pts who did not achieve CR/CRi with ENAm, a subset of patients achieved CR/CRi with addition of AZA. This combined approach of serial therapy with ENA monotherapy followed by AZA addition in pts with sub-optimal response resulted in a mOS exceeding 2 years for pts enrolled on study. Further focus on improving response among patients with IDH2 R172 mutations, identifying subsets of pts not responding to ENA monotherapy, and integrating new targeted agents into this treatment regimen are warranted. Figure 1 Disclosures Stein: Syndax: Consultancy, Research Funding; Celgene Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Daiichi-Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Astellas Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Consultancy; Agios Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bayer: Research Funding; Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy; Biotheryx: Consultancy; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; PTC Therapeutics: Membership on an entity's Board of Directors or advisory committees; Syros: Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy. Borate:Genentech: Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Jazz Pharmaceuticals: Research Funding; AbbVie: Other: Investigator in AbbVie-funded clinical trials; Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding. Baer:Takeda: Other: Institutional research funding; AbbVie: Other: Institutional research funding; Astellas: Other: Institutional research funding; Forma: Other: Institutional research funding; Kite: Other: Institutional research funding; Oscotec: Other: Institutional research funding; Incyte: Other: Institutional research funding. Kovacsovics:Agios: Honoraria; Astella: Honoraria; Pfizer: Research Funding; Novartis: Research Funding; AbbVie: Research Funding; Jazz: Honoraria. Schiller:Astellas Pharma: Honoraria, Research Funding; Celator: Research Funding; Constellation: Research Funding; Abbvie: Research Funding; Actinium: Research Funding; Ariad: Research Funding; Stemline: Speakers Bureau; Cyclacel: Research Funding; Daiichi Sankyo: Research Funding; Deciphera: Research Funding; DeltaFly: Research Funding; Bristol-Myers Squibb: Current equity holder in publicly-traded company, Research Funding; Forma: Research Funding; FujiFilm: Research Funding; Gamida: Research Funding; Genentech-Roche: Research Funding; Geron: Research Funding; Jazz Pharmaceuticals: Research Funding; Karyopharm: Research Funding; Kite Pharma: Research Funding; Mateon: Research Funding; MedImmune: Research Funding; Onconova: Research Funding; Pfizer: Current equity holder in publicly-traded company, Research Funding; Regimmune: Research Funding; Samus: Research Funding; Sangamo: Research Funding; Tolero: Research Funding; Trovagene: Research Funding; Kaiser Permanente: Consultancy; Johnson & Johnson: Current equity holder in publicly-traded company; Agios: Consultancy, Research Funding, Speakers Bureau; Amgen: Consultancy, Current equity holder in publicly-traded company, Research Funding, Speakers Bureau; AstraZeneca: Consultancy; Incyte: Consultancy, Research Funding, Speakers Bureau; Novartis: Consultancy, Research Funding; Ono Pharma: Consultancy; Celgene: Research Funding, Speakers Bureau; Sanofi: Speakers Bureau; Gilead: Speakers Bureau. Olin:Astellas: Other: Site PI; Genentech: Other: Site PI; Pfizer: Other: Site PI; Daiichi Sankyo: Other: Site PI; Genentech: Consultancy; Amgen: Consultancy. Foran:Trillium: Research Funding; Xencor: Research Funding; H3Biosciences: Research Funding; Agios: Honoraria, Research Funding; Pfizer: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; Abbvie: Research Funding; Boehringer Ingelheim: Research Funding; Actinium: Research Funding; Aprea: Research Funding; Aptose: Research Funding; Kura Oncology: Research Funding; Takeda: Research Funding; Revolution Medicine: Consultancy; Novartis: Membership on an entity's Board of Directors or advisory committees; Servier: Membership on an entity's Board of Directors or advisory committees. Lin:Trovagene: Research Funding; Tolero Pharmaceuticals: Research Funding; Seattle Genetics: Research Funding; Prescient Therapeutics: Research Funding; Abbvie: Research Funding; Bio-Path Holdings: Research Funding; Astellas Pharma: Research Funding; Aptevo: Research Funding; Incyte: Research Funding; Pfizer: Research Funding; Mateon Therapeutics: Research Funding; Ono Pharmaceutical: Research Funding; Jazz: Research Funding; Gilead Sciences: Research Funding; Genetech-Roche: Research Funding; Celyad: Research Funding; Celgene: Research Funding. Patel:DAVA Pharmaceuticals: Honoraria; Celgene: Consultancy, Speakers Bureau; Agios: Consultancy; France Foundation: Honoraria. Foster:Daiichi Sankyo: Consultancy; Bellicum Pharmaceuticals: Research Funding; Macrogenics: Consultancy, Research Funding. Druker:Leukemia & Lymphoma Society: Research Funding; Henry Stewart Talks: Patents & Royalties; Iterion Therapeutics (formerly Beta Cat Pharmaceuticals): Membership on an entity's Board of Directors or advisory committees; Vivid Biosciences: Membership on an entity's Board of Directors or advisory committees; GRAIL: Consultancy, Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; Patient True Talks: Consultancy; The RUNX1 Research Program: Membership on an entity's Board of Directors or advisory committees; Third Coast Therapeutics: Membership on an entity's Board of Directors or advisory committees; VB Therapeutics: Membership on an entity's Board of Directors or advisory committees; Gilead Sciences: Consultancy, Membership on an entity's Board of Directors or advisory committees; Millipore (formerly Upstate Biotechnology): Patents & Royalties; MolecularMD (acquired by ICON): Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Novartis Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding; McGraw Hill: Patents & Royalties; Merck & Co: Patents & Royalties; Cepheid: Consultancy, Membership on an entity's Board of Directors or advisory committees; Dana-Farber Cancer Institute: Patents & Royalties; EnLiven: Consultancy, Research Funding; Aptose Therapeutics Inc. (formerly Lorus): Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; ARIAD: Research Funding; Blueprint Medicines: Consultancy, Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; ALLCRON: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Research Funding; Aileron Therapeutics: Membership on an entity's Board of Directors or advisory committees; Pfizer: Research Funding; Oregon Health & Science University: Patents & Royalties. Byrd:Acerta Pharma: Research Funding; Syndax: Research Funding; Vincera: Research Funding; Pharmacyclics LLC, an AbbVie Company, Janssen, Novartis, Gilead, TG Therapeutics: Other; Pharmacyclics LLC, an AbbVie Company, Gilead, TG Therapeutics, Novartis, Janssen: Speakers Bureau; Novartis: Research Funding; Kartos Therapeutics: Research Funding; Trillium: Research Funding; Leukemia and Lymphoma Society: Other; Janssen: Consultancy; Pharmacyclics LLC, an AbbVie Company, Gilead, TG Therapeutics, BeiGene: Research Funding. Levine:Loxo: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; C4 Therapeutics: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; Imago: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Research Funding; Qiagen: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Prelude Therapeutics: Research Funding; Amgen: Honoraria; Astellas: Consultancy; Morphosys: Consultancy; Novartis: Consultancy; Isoplexis: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy; Lilly: Consultancy, Honoraria; Roche: Consultancy, Honoraria, Research Funding; Gilead: Honoraria. Mims:Abbvie: Membership on an entity's Board of Directors or advisory committees; Kura Oncology: Membership on an entity's Board of Directors or advisory committees; Leukemia and Lymphoma Society: Other: Senior Medical Director for Beat AML Study; Jazz Pharmaceuticals: Other: Data Safety Monitoring Board; Syndax Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Agios: Consultancy; Novartis: Speakers Bureau. OffLabel Disclosure: Enasidenib is not approved for the treatment of newly diagnosed AML.

Introduction: Hypomethylating agents (HMAs) or DNA methyltransferase inhibitors (DNMTi) such as decitabine or azacitidine are established standard of care for the treatment of MDS and CMML. The oral bioavailability of these agents has been limited due to rapid degradation by cytidine deaminase (CDA) in the gut and liver, hence requiring intravenous infusion or subcutaneous injections daily for 5-7 days every month (m). This parenteral administration requirement adds significant burden to older cancer patients due to daily time commitment and travel to treatment centers. It also increases exposure to and infection risk with SARS-CoV-2 during the COVID-19 pandemic. Oral decitabine 35 mg/cedazuridine 100 mg (ASTX727) is an oral fixed dose combination drug of decitabine and the CDA inhibitor cedazuridine that have shown 99% (90% CI 93% to 106%) equivalent exposure to standard dose IV decitabine 20 mg/m2 in a randomized cross-over study (Garcia-Manero et al, ASH 2019). Here, we present the clinical efficacy and safety results of oral decitabine/cedazuridine from 133 patient study in MDS and CMML (ASTX727-02 ASCERTAIN study). Methods: We used a randomized cross over design where patients were randomized in the first 2 cycles 1:1 to either Sequence A: decitabine 35 mg/ cedazuridine 100 mg in Cycle 1 followed by IV decitabine at 20 mg/m2 in Cycle 2, or Sequence B: IV decitabine in Cycle 1 followed by oral decitabine/cedazuridine in Cycle 2 to do an intra-patient comparison of decitabine PK (primary PK endpoint: decitabine AUC equivalence over 5 days of dosing). Cycles were repeated every 28 days. All patients received oral decitabine/cedazuridine in all subsequent cycles from Cycle 3 onwards until disease progression or unacceptable toxicity. Patients were eligible as per the FDA-approved label of IV decitabine (MDS patients by FAB classification including CMML, or MDS IPSS Intermediate-1, 2 or high-risk patients). Clinical endpoints were best response as assessed by an independent expert panel according to International Working Group (IWG) 2006 response criteria, transfusion independence for at least 8 or 16 consecutive weeks, overall survival, and safety. Adverse events (AEs) were graded by Common Terminology Criteria for Adverse Events (CTCAE) v 4.03. Results: 138 subjects were randomized, of whom 133 were treated on study. The median age was 71.0 years (range 44-88), 65% were male, 88% MDS and 12% CMML, 43% were either red blood cells (RBCs) or platelets transfusion-dependent at baseline, 25% had poor-risk cytogenetics, and 42% had baseline bone marrow blasts >5%. At the data cutoff for the response analysis, the median duration of follow up was 12.6 m (range 9.3 to 20.5 m) with median number of treatment cycles of 8 (range 1 to 18). Of the 133 treated patients the best response was complete response (CR) in 28 patients (21%; 95% CI 15-29%), marrow (m)CR with hematological improvement (HI) in 20 patients (15%), mCR without HI in 23 patients (17.3%), and HI in 10 patients (7.5%) for an overall objective response (CR+mCR+HI) in 81 patients (61%; 95% CI 52-69%). Median duration of CR was 7.5 m (range 1.6 to 17.5 m), and median time to CR was 4.3 m (range 2.1 to 15.2 m). Of the 133 treated patients 27 (20%) went on to receive allogeneic hematopoietic cell transplant. Of the 57 patients who were either RBCs or platelets transfusion-dependent at baseline, 30 (53%) became transfusion independent for both RBCs and platelets for at least 8 consecutive weeks, and 19 (33%) were both RBCs and platelets transfusion independent for at least 16 consecutive weeks. Median survival has not been reached. Most common Treatment-Emergent AEs of Grade ≥3 regardless of causality were neutropenia in 51.5%, thrombocytopenia in 50%, anemia in 40%, febrile neutropenia in 26%, leukopenia in 21%, pneumonia in 12%, and sepsis in 7% of patients treated with oral decitabine/cedazuridine (excluding the IV decitabine cycle). Summary/Conclusions: Efficacy and safety from oral decitabine 35 mg/ cedazuridine 100 mg daily for 5 days every 28 days are consistent with clinical data from standard IV decitabine 20 mg/m2 daily for 5 days. Oral decitabine/cedazuridine is the only oral HMA with systemic exposure equivalent to its injectable drug. Further investigation of oral decitabine/cedazuridine in all-oral combination studies is warranted and underway. Disclosures Savona: BMS: Consultancy; AbbVie: Consultancy; Gilead: Consultancy; Karyopharm: Consultancy, Current equity holder in publicly-traded company; Ryvu: Consultancy; Boehringer Ingelheim: Patents & Royalties; Takeda: Consultancy, Research Funding; Incyte: Consultancy, Research Funding; Astex: Consultancy, Research Funding; Sunesis: Consultancy, Research Funding; TG Therapeutics: Consultancy, Research Funding. Griffiths:Celgene/BMS: Honoraria, Research Funding; Genentech Inc: Research Funding; Boston Biomedical: Honoraria; AbbVie Inc: Honoraria; Persimmune: Research Funding; Novartis: Honoraria, Research Funding; Alexion Pharmaceuticals: Honoraria, Research Funding; Astex Pharmceuticals: Research Funding. Zeidan:CCITLA: Other; Seattle Genetics: Consultancy, Honoraria; BeyondSpring: Consultancy, Honoraria; Taiho: Consultancy, Honoraria; Cardinal Health: Consultancy, Honoraria; Epizyme: Consultancy, Honoraria; Leukemia and Lymphoma Society: Other; Jazz: Consultancy, Honoraria; Trovagene: Consultancy, Honoraria, Research Funding; Ionis: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Research Funding; Astex: Research Funding; Daiichi Sankyo: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria, Research Funding; Otsuka: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria, Research Funding; Acceleron: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Research Funding; Boehringer-Ingelheim: Consultancy, Honoraria, Research Funding; Celgene / BMS: Consultancy, Honoraria, Research Funding; Agios: Consultancy, Honoraria; ADC Therapeutics: Research Funding; Aprea: Research Funding; MedImmune/Astrazeneca: Research Funding; Cardiff Oncology: Consultancy, Honoraria, Other; Incyte: Consultancy, Honoraria, Research Funding; Astellas: Consultancy, Honoraria. Patel:DAVA Pharmaceuticals: Honoraria; France Foundation: Honoraria; Celgene: Consultancy, Speakers Bureau; Agios: Consultancy. Keating:Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Hoffman La Roche: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Merck: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Consultancy; Servier: Membership on an entity's Board of Directors or advisory committees; Shire: Membership on an entity's Board of Directors or advisory committees; Taiho: Membership on an entity's Board of Directors or advisory committees. Dao:Astex Pharmaceuticals, Inc.: Current Employment. Fazal:Jansen: Speakers Bureau; Gilead/Kite: Consultancy, Speakers Bureau; Takeda: Consultancy, Speakers Bureau; Jazz Pharma: Consultancy, Speakers Bureau; Karyopham: Speakers Bureau; Celgene: Speakers Bureau; Glaxosmith Kline: Consultancy, Speakers Bureau; Incyte Corporation: Consultancy, Honoraria, Speakers Bureau; Agios: Consultancy, Speakers Bureau; Stemline: Consultancy, Speakers Bureau; Amgen: Consultancy, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Odenike:Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Astex Pharmaceuticals, NS Pharma, Gilead Sciences, Janssen Oncology, Oncotherapy, Agios, CTI/Baxalta, Aprea: Other: Institutional research funding; Astra Zeneca: Research Funding; Incyte: Other: Institutional research funding; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Impact Biomedicines: Consultancy, Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Kantarjian:Abbvie: Honoraria, Research Funding; BioAscend: Honoraria; Delta Fly: Honoraria; Ascentage: Research Funding; Janssen: Honoraria; Novartis: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding; Sanofi: Research Funding; Actinium: Honoraria, Membership on an entity's Board of Directors or advisory committees; Immunogen: Research Funding; Aptitute Health: Honoraria; BMS: Research Funding; Daiichi-Sankyo: Honoraria, Research Funding; Jazz: Research Funding; Oxford Biomedical: Honoraria; Amgen: Honoraria, Research Funding; Adaptive biotechnologies: Honoraria. DeZern:MEI: Consultancy; Celgene: Consultancy, Honoraria; Astex: Research Funding; Abbvie: Consultancy. Roboz:Novartis: Consultancy; Janssen: Consultancy; Celgene: Consultancy; Astex: Consultancy; Amphivena: Consultancy; Agios: Consultancy; Pfizer: Consultancy; Abbvie: Consultancy; Array BioPharma: Consultancy; Bayer: Consultancy; Celltrion: Consultancy; Eisai: Consultancy; Jazz: Consultancy; Roche/Genentech: Consultancy; Sandoz: Consultancy; Actinium: Consultancy; Argenx: Consultancy; Astellas: Consultancy; Daiichi Sankyo: Consultancy; AstraZeneca: Consultancy; Orsenix: Consultancy; Otsuka: Consultancy; Takeda: Consultancy; Trovagene: Consultancy; Cellectis: Research Funding; Jasper Therapeutics: Consultancy; Epizyme: Consultancy; Helsinn: Consultancy; MEI Pharma: Consultancy. Busque:Pfizer: Honoraria; BMS: Honoraria; Novartis: Honoraria. Wells:Alexion: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Leber:Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Otsuka Pharmaceutical: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda/Palladin: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Treadwell: Honoraria, Membership on an entity's Board of Directors or advisory committees; Lundbeck: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Alexion: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS/Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees. Hao:Astex Pharmaceuticals, Inc.: Current Employment. Keer:Astex Pharmaceuticals, Inc.: Current Employment. Azab:Astex Pharmaceuticals, Inc.: Current Employment. Garcia-Manero:Acceleron Pharmaceuticals: Consultancy, Honoraria; AbbVie: Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; H3 Biomedicine: Research Funding; Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Astex Pharmaceuticals: Consultancy, Honoraria, Research Funding; Amphivena Therapeutics: Research Funding; Helsinn Therapeutics: Consultancy, Honoraria, Research Funding; Onconova: Research Funding; Merck: Research Funding; Jazz Pharmaceuticals: Consultancy; Celgene: Consultancy, Honoraria, Research Funding; Novartis: Research Funding.

Introduction: Hypomethylating agents (HMAs) such as decitabine (DEC) or azacitidine (AZA) are FDA approved therapies for patients with different myeloid malignancies as single agent or in combination with venetoclax. Both DEC and AZA require IV infusion for 1 hour or subcutaneous (SC) injections daily for 5-7 days of every 28-day treatment cycle. They both have limited oral bioavailability due to rapid degradation by cytidine deaminase (CDA) in the gut and liver. An orally bioavailable HMA option could reduce clinic visit frequency and reduce infusions/injections related adverse events and burden. ASTX727 is an oral tablet comprised of a fixed-dose combination (FDC) of CDA inhibitor cedazuridine (C) at 100 mg with DEC at 35 mg. In a phase 2 study, C-DEC (ASTX727) demonstrated pharmacokinetic (PK) AUC exposure similar to IV-DEC at 20mg/m2 with comparable clinical activity and safety (Garcia-Manero, et al, 15th Int'l MDS Symposium, 2019). We describe here the results of a phase 3 study designed to demonstrate exposure bioequivalence of oral C-DEC and IV-DEC and generate clinical data using C-DEC in a larger population (ASCERTAIN study). Methods: The study used a randomized cross over design where patients were randomized 1:1 to either Sequence A: C-DEC (100 mg/35 mg respectively) in Cycle 1 followed by IV-DEC at 20 mg/m2 in Cycle 2, or Sequence B receiving IV-DEC in Cycle 1 followed by C-DEC on Cycle 2 to compare PK (primary endpoint AUC equivalence over 5 days of dosing) and pharmacodynamic (PD) of DNA demethylation using LINE-1 assay. All patients received C-DEC in all subsequent cycles from Cycle 3 onwards until treatment discontinuation to study clinical efficacy and safety of C-DEC. Patients were eligible as per the FDA-approved label (MDS IPSS Intermediate [Int]-1,-2 or high risk[HR] and CMML patients). Clinical responses were assessed by an independent expert panel according to International Working Group (IWG) 2006 response criteria. Adverse events (AEs) were graded by Common Terminology Criteria for Adverse Events (CTCAE) v 4.03. Results: 138 patients were randomized, of whom 133 were treated with median age of 71.0 years (range 44-88), median weight was 83.1 kg (range 45-158), and median BSA was 1.99 m2 (range 1.4-2.9 m2). The IPSS status of the patients were Int-1 in 44%, Int-2 in 20%, and HR in 16%, and 12% of pts had CMML. Patients in the two arms were well balanced regarding cytogenetic risk, baseline hemoglobin, neutrophils, platelets, or red blood cell or platelet transfusion dependence. For the primary end point, the decitabine AUC0-24 (h*ng/mL) 5-Day geometric mean estimate was 856 from the C-DEC and 865 from IV-DEC resulting in an oral/IV AUC ratio of 98.9% (90% CI of 92.7-105.6%). All sensitivity and secondary exposure analyses confirmed the primary results. Comparison of hypomethylating activity as measured by LINE-1 demethylation showed difference between oral C-DEC and IV-DEC demethylation of <1% and the 95% CI of the difference included zero. Safety findings were consistent with those anticipated for IV-DEC (related Grade ≥ 3 AEs in more than 5% were thrombocytopenia, neutropenia, anemia, febrile neutropenia, and leukopenia). As of the data cutoff, median follow up was 5.2 months ( IQR 3.5-8.0) with 101 patients evaluable for response . Preliminary response analysis of all evaluable patients showed best responses of complete response (CR) in 12 patients (11.9%), marrow (m)CR in 46 (45.5%) including 14 patients (13.9%) with mCR + hematological improvement (HI), hematologic improvement (HI) in 7 (6.9%) resulting in an objective response rate (CR+mCR+ HI) in 65 patients (64%). In addition, of all 133 treated patients, 16 patients (12%) underwent hematopoietic cell transplant. Updated response data will be presented at the meeting. Summary/Conclusions: This randomized phase 3 study demonstrates that C-DEC, the oral FDC of cedazuridine/decitabine (100 mg/35 mg) resulted in an equivalent DEC exposure to IV-DEC at 20 mg/m2 over 5 days. Safety findings are consistent with those anticipated with IV-DEC with no clinically significant GI toxicity. Preliminary clinical activity is also consistent with published data from IV-DEC. C-DEC is an oral HMA alternative to IV-DEC. Combination studies with other oral agents are being planned. Disclosures Garcia-Manero: Amphivena: Consultancy, Research Funding; Helsinn: Research Funding; Novartis: Research Funding; AbbVie: Research Funding; Celgene: Consultancy, Research Funding; Astex: Consultancy, Research Funding; Onconova: Research Funding; H3 Biomedicine: Research Funding; Merck: Research Funding. Griffiths:New Link Genetics: Consultancy; Astex Phramaceuticals/Otsuka Pharmaceuticals: Consultancy, Research Funding; Persimmune: Consultancy; Boston Scientific: Consultancy; Genentech, Inc.: Research Funding; Genentech, Inc.: Research Funding; Novartis Inc.: Consultancy; Novartis Inc.: Consultancy; Partner Therapeutics: Consultancy; Astex Phramaceuticals/Otsuka Pharmaceuticals: Consultancy, Research Funding; Onconova Therapeutics: Other: PI on a clinical trial; Celgene, Inc: Consultancy, Research Funding; Abbvie, Inc.: Consultancy; Celgene, Inc: Consultancy, Research Funding; Persimmune: Consultancy; Partner Therapeutics: Consultancy; Boston Scientific: Consultancy; New Link Genetics: Consultancy; Onconova Therapeutics: Other: PI on a clinical trial; Abbvie, Inc.: Consultancy, PI on a clinical trial; Appelis Pharmaceuticals: Other: PI on a clinical trial; Appelis Pharmaceuticals: Other: PI on a clinical trial. Yee:Celgene: Honoraria, Research Funding; Novartis: Honoraria, Research Funding. Zeidan:Ariad: Honoraria; Acceleron Pharma: Consultancy, Honoraria, Research Funding; Celgene Corporation: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Honoraria, Research Funding; Otsuka: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria, Research Funding; Medimmune/AstraZeneca: Research Funding; Astellas: Honoraria; Seattle Genetics: Honoraria; Cardinal Health: Honoraria; Novartis: Honoraria; Agios: Honoraria; Daiichi Sankyo: Honoraria; BeyondSpring: Honoraria; Boehringer-Ingelheim: Consultancy, Honoraria, Research Funding; Trovagene: Consultancy, Honoraria, Research Funding; Incyte: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; ADC Therapeutics: Research Funding; Jazz: Honoraria. Al-Kali:Astex Pharmaceuticals, Inc.: Research Funding. Dao:Incyte Corporation: Membership on an entity's Board of Directors or advisory committees, Research Funding. Patel:Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Dava Oncology: Honoraria; France Foundation: Honoraria. Sabloff:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; ASTX: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi Canada: Research Funding; Actinium Pharmaceuticals, Inc: Membership on an entity's Board of Directors or advisory committees; Pfizer Canada: Honoraria, Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; Astellas Pharma Canada: Honoraria, Membership on an entity's Board of Directors or advisory committees. Keating:Sanofi: Membership on an entity's Board of Directors or advisory committees; Hoffman La Roche: Membership on an entity's Board of Directors or advisory committees; Shire: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Consultancy; Celgene: Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria. Fazal:Janssen: Honoraria, Speakers Bureau; Takeda: Honoraria, Speakers Bureau; Gilead: Consultancy, Honoraria, Speakers Bureau; Pfizer: Speakers Bureau; Novartis: Consultancy, Honoraria, Speakers Bureau; Incyte: Consultancy, Honoraria, Speakers Bureau; BMS: Consultancy, Honoraria, Speakers Bureau; Jazz: Consultancy, Honoraria, Speakers Bureau; Celgene: Speakers Bureau; Karyopharm: Honoraria, Speakers Bureau. Odenike:AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen Oncology: Research Funding; Astra Zeneca: Research Funding; Gilead Sciences: Research Funding; Agios: Research Funding; CTI/Baxalta: Research Funding; Astex Pharmaceuticals: Research Funding; Incyte: Research Funding; NS Pharma: Research Funding; Oncotherapy: Research Funding. DeZern:Astex Pharmaceuticals, Inc.: Consultancy; Celgene: Consultancy. O'Connell:Astex: Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: Research Funding; Pfizer: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; Shionogi: Membership on an entity's Board of Directors or advisory committees. Roboz:Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Jazz: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees; Orsenix: Consultancy, Membership on an entity's Board of Directors or advisory committees; Otsuka: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Trovagene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sandoz: Consultancy, Membership on an entity's Board of Directors or advisory committees; Roche/Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees; MEI Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Eisai: Consultancy, Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celltrion: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bayer: Consultancy, Membership on an entity's Board of Directors or advisory committees; Astellas: Consultancy, Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Actinium: Consultancy, Membership on an entity's Board of Directors or advisory committees; Agios: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amphivena: Consultancy, Membership on an entity's Board of Directors or advisory committees; Argenx: Consultancy, Membership on an entity's Board of Directors or advisory committees; Astex: Consultancy, Membership on an entity's Board of Directors or advisory committees. Oganesian:Astex Pharmaceuticals, Inc.: Employment. Hao:Astex Pharmaceuticals, Inc.: Employment. Keer:Astex Pharmaceuticals, Inc.: Employment. Azab:Astex Pharmaceuticals, Inc.: Employment. Savona:Incyte Corporation: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene Corporation: Membership on an entity's Board of Directors or advisory committees; AbbVie: Membership on an entity's Board of Directors or advisory committees; Boehringer Ingelheim: Patents & Royalties; Sunesis: Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; TG Therapeutics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Selvita: Membership on an entity's Board of Directors or advisory committees; Karyopharm Therapeutics: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees.

Introduction: Inherited predisposition to myeloid malignancies in adults may be more common than previously suggested with recent studies suggesting a prevalence of candidate predisposition alleles in 15-20% of patients. An inherited predisposition may not be considered in older AML patients despite significant clinical implications for family members as potential stem cell transplant donors. To better define the role of inherited genetic alterations in older AML patients , we analyzed a unique cohort of newly diagnosed older (>60 years) patients enrolled in) Beat AML® Master Trial(BAMT) for candidate genes associated with a known or putative inherited cancer predisposition. Methods: We analyzed extracted DNA from skin and/or saliva samples compared to paired leukemia samples of 176 AML patients enrolled in the BAMT. All samples underwent genomic profiling using a modified FoundationOne®Heme platform (capture-based) and/or the Oregon Health Sciences University panel (amplicon-based), evaluating 477 and 220 genes respectively, with a known role in hematologic malignancies. Germline(GL) variants were identified by the haplotype-based Bayesian genetic variant detector FreeBayes and using variant allele frequency(VAF) values. The pathogenicity and clinical significance of the variants was interpreted according to the 2015 ACMG/AMP guidelines while the AMP/CAP/ASCO guidelines and various disease databases were used in the somatic variant calls. Results: -The mutational landscape of the 176 newly diagnosed older AML patients is detailed in Table 1. Our cohort has a higher proportion of adverse risk patients, consistent with an older AML patient population. 27 pathogenic or likely pathogenic GL variants were detected in 24 AML patients, with a germline mutation prevalence of 14% in this cohort. Deleterious GL mutations were found in the gene DDX41 (5), followed by SBDS (4), CHEK2 (4), MPL (3), BRCA2 (2), HAX1 (2), DNAH9 (2), FANCA (1), FANCL (1), SAMD9 (1), BLM (1), and ATM (1) (Table 2). The types of mutations included missense mutations (9), nonsense mutations (8), frameshift mutations (7), splice site mutations (2), and an exonic deletion (1). Family history of leukemia was available on 129 patients from this cohort. 12 patients have at least one family member with AML. Of these 12 patients, 2 had a deleterious GL alteration identified. Along with the 14% prevalence of pathogenic/likely pathogenic GL mutations , there were an additional 181 GL variants of unknown significance (VUS) in 102 patients, seen in genes implicated in inherited predisposition to hematologic malignancies, most commonly variants in DOCK8 and CREBBP(>5% VUS) with both genes being implicated in leukemogenesis . As skin and/or saliva samples were collected at the time of AML diagnosis, tumor-in-normal presence was expectedly observed. The median VAF for somatic mutations was significantly lower (p < 0.0001) in skin (median 6%; mean 9%; standard deviation (SD) 10%; N=562 variants) than in saliva (median 17%; mean 21%; SD 16%; N=368 variants). In 37 patients who had both saliva and skin tissue concomitantly ,skin had a significantly lower tumor-in-normal presence (median VAF 5%, mean 8%, SD 8%;) than saliva (median 15%, mean 20%, SD 16%)(p < 0.0001). Conclusions: We found a prevalence of 14% pathogenic/ likely pathogenic GL mutations in cancer predisposition genes in this unique cohort of newly diagnosed older AML patients. This finding has potential clinical implications for patients and family members. We also found a large number of VUS in genes implicated in hematological malignancies. Additional studies linking candidate VUS' to familial predisposition to understand contribution to AML predisposition are needed. We are in the process of comparing the manual curation of ACMG classification of pathogenicity with a computational curation algorithm to assess the potential for automated classification of GL variants. Our study suggests the choice of source for germline DNA in patients with AML is variably impacted by leukemic contamination. Cultured skin fibroblasts are the current standard for tumor-normal paired genotyping, with the caveat of being labor intensive and not routinely performed in clinical diagnostic laboratories. This is a critical consideration for rapid GL screening of patients and family members with hematologic malignancies and suspected cancer predisposition. Disclosures Borate: Novartis: Consultancy; Takeda: Consultancy; Pfizer: Consultancy; Daiichi Sankyo: Consultancy; AbbVie: Consultancy. Mims:Abbvie: Membership on an entity's Board of Directors or advisory committees; Agios Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; PTC Therapeutics: Membership on an entity's Board of Directors or advisory committees; Astellas Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees. Stein:Agios: Consultancy, Membership on an entity's Board of Directors or advisory committees; Astellas Pharma US, Inc: Membership on an entity's Board of Directors or advisory committees; Celgene Corporation: Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo, Inc.: Membership on an entity's Board of Directors or advisory committees; Bioline: Membership on an entity's Board of Directors or advisory committees; Genentech: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; PTC Therapeutics: Membership on an entity's Board of Directors or advisory committees; Syros: Membership on an entity's Board of Directors or advisory committees. Patel:Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Dava Oncology: Honoraria; France Foundation: Honoraria. Baer:Astellas: Research Funding; Abbvie: Research Funding; AI Therapeutics: Research Funding; Forma: Research Funding; Incyte: Research Funding; Kite: Research Funding; Takeda: Research Funding. Stock:Agios: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees; UpToDate: Honoraria; Daiichi: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Kite, a Gilead Company: Membership on an entity's Board of Directors or advisory committees; Research to Practice: Honoraria. Schiller:Bristol Myer Squibb: Research Funding; Celgene: Research Funding, Speakers Bureau; Constellation Pharmaceutical: Research Funding; Daiichi Sankyo: Research Funding; Agios: Research Funding, Speakers Bureau; Amgen: Other, Research Funding; Astellas: Research Funding; Biomed Valley Discoveries: Research Funding; Eli Lilly and Company: Research Funding; FujiFilm: Research Funding; Genzyme: Research Funding; Gilead: Research Funding; Incyte: Research Funding; J&J: Research Funding; Jazz Pharmaceuticals: Honoraria, Research Funding; Karyopharm: Research Funding; Novartis: Research Funding; Onconova: Research Funding; Pfizer Pharmaceuticals: Equity Ownership, Research Funding; Sangamo Therapeutics: Research Funding. Blum:AmerisourceBergen: Consultancy; Forma: Research Funding; Xencor: Research Funding; Boehringer Ingelheim: Research Funding; Celgene: Research Funding; Astellas,: Research Funding. Shami:JSK Therapeutics: Employment, Equity Ownership; Amgen: Research Funding; Pfizer: Research Funding; Cantex: Research Funding; Aptevo: Research Funding; Jazz: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; Agios: Consultancy, Honoraria; Lone Star Thiotherapies: Equity Ownership. Foran:Agios: Honoraria, Research Funding. Byrd:Acerta: Research Funding; Gilead: Other: Travel Expenses, Research Funding, Speakers Bureau; Genentech: Research Funding; Novartis: Other: Travel Expenses, Speakers Bureau; Pharmacyclics LLC, an AbbVie Company: Other: Travel Expenses, Research Funding, Speakers Bureau; TG Therapeutics: Other: Travel Expenses, Research Funding, Speakers Bureau; Ohio State University: Patents & Royalties: OSU-2S; BeiGene: Research Funding; Janssen: Consultancy, Other: Travel Expenses, Research Funding, Speakers Bureau. Druker:OHSU (licensing fees): Patents & Royalties: #2573, Constructs and cell lines harboring various mutations in TNK2 and PTPN11, licensing fees ; Bristol-Myers Squibb: Other: PI or co-investigator on clinical trial(s) funded via contract with OHSU., Research Funding; Novartis: Other: PI or co-investigator on clinical trial(s) funded via contract with OHSU., Patents & Royalties: Patent 6958335, Treatment of Gastrointestinal Stromal Tumors, exclusively licensed to Novartis, Research Funding; Monojul: Other: former consultant; Vivid Biosciences: Membership on an entity's Board of Directors or advisory committees, Other: Stock options; Beat AML LLC: Other: Service on joint steering committee; Merck & Co: Patents & Royalties: Dana-Farber Cancer Institute license #2063, Monoclonal antiphosphotyrosine antibody 4G10, exclusive commercial license to Merck & Co; Dana-Farber Cancer Institute (antibody royalty): Patents & Royalties: #2524, antibody royalty; Aileron Therapeutics: #2573, Constructs and cell lines harboring various mutations in TNK2 and PTPN11, licensing fees , Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Patents & Royalties, Research Funding; Pfizer: Research Funding; ALLCRON: Membership on an entity's Board of Directors or advisory committees; Amgen: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Aptose Biosciences: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Beta Cat: Membership on an entity's Board of Directors or advisory committees, Other: Stock options; The RUNX1 Research Program: Membership on an entity's Board of Directors or advisory committees; Patient True Talk: Consultancy; GRAIL: Equity Ownership, Other: former member of Scientific Advisory Board; Cepheid: Consultancy, Honoraria; Blueprint Medicines: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Burroughs Wellcome Fund: Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy; Pfizer: Other: PI or co-investigator on clinical trial(s) funded via contract with OHSU., Research Funding; ICON: Other: Scientific Founder of Molecular MD, which was acquired by ICON in Feb. 2019; CureOne: Membership on an entity's Board of Directors or advisory committees; Gilead Sciences: Other: former member of Scientific Advisory Board. Vergilio:Foundation Medicine, Inc.: Employment; F. Hoffman La Roche, Ltd.: Equity Ownership. Levine:Imago Biosciences: Membership on an entity's Board of Directors or advisory committees; Prelude Therapeutics: Research Funding; C4 Therapeutics: Membership on an entity's Board of Directors or advisory committees; Roche: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Amgen: Honoraria; Gilead: Consultancy; Lilly: Honoraria; Qiagen: Membership on an entity's Board of Directors or advisory committees; Isoplexis: Membership on an entity's Board of Directors or advisory committees; Loxo: Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy.

*equal contribution of AB, RLL, BD and JCB Background: Acute myeloid leukemia (AML) is common with increasing age, and older adults with AML rarely achieve long-term remission with chemotherapy. Gene discovery studies in older adults with AML have shown that this malignancy is characterized by a multitude of somatic genomic alterations beginning with initiating somatic events followed by acquisition of collaborative transforming mutations. Despite these important biologic insights, current therapeutic approaches to AML remain limited, particularly in adults ≥ 60 years of age. The Beat AML trial was designed to assess the feasibility of using genetic profiling to assign patients (pts) to molecularly defined, subtype-specific therapies within 7 days of the initial diagnosis in a multi-center clinical trial setting, and to delineate the role of molecularly informed first-line treatment of AML with mechanism based novel therapies. Methods: Treatment-naïve patients with AML were enrolled in this prospective trial which offered accelerated cytogenetic and comprehensive mutational testing within 7 days followed by treatment assignment using these molecular data. Pt eligibility included age ≥ 60 years with non-APML AML, no known CNS leukemia, no prior hypomethylating agent (HMA) therapy and no clinical need for emergent therapy. Eligible pts were profiled by local cytogenetics analysis and using a central next generation sequencing (NGS) assay (Foundation Medicine, Inc.) with all molecular data required for treatment assignment (TA) obtained < 7 days. TA was made centrally using a pre-determined algorithm considering somatic cytogenetic and molecular alterations in the dominant clone, available targeted therapeutics for specific AML subsets, and the likelihood of cure with intensive chemotherapy. Results: From November 2016 to January 2019, 487 pts with a suspected diagnosis of AML had enrolled at 14 clinical sites; 395 were eligible for the study (77% of the patients not eligible for the study had an alternative diagnosis). The median age of eligible patients was 72 years (range: 60 to 92) with 38% being≥ 75 years and 16% with treatment-related AML. From the 395 eligible patients, 374 (94.7%) were centrally assigned to the different cytogenetic/genomic groups within 7 days. The most common groups were TP53 mutated (19%) and marker negative (18%) molecular groups. The Beat AML trial is dynamic by design, thereby allowing different arms to open over time; all trial arms are designed to evaluate for substantial clinical efficacy in small, molecularly defined patient subsets. As shown in Figure 1, 224 patients (57%) had a TA and consented to a BEAT AML sub-study. Of the remaining 171 patients, 103 received standard therapy defined as induction therapy (7+3) or hypomethylation agent (25 before TA and 78 after TA), 28 received an alternative investigational agent (5 before TA and 23 after TA), 38 received palliative care, and 2 had an unknown treatment status and are grouped with the palliative care patients in subsequent analyses; 9 patients died before TA (2 who received standard therapy and 7 in the palliative care group). Demographic, clinical, performance and molecular characteristics were not largely different between pts who elected targeted therapy as part of the BEAT AML trial versus those who elected standard therapy. As shown in Figure 2, the overall survival was significantly longer for patients enrolled in a targeted therapy arm as part of the BEAT AML trial compared to those who elected standard therapy. (p<0.0001). The 30-day estimated death rate was 3.7% (95% CI: 1.9-7.2) for patients electing treatment on a BEAT AML sub-study, 20.4% (95% CI: 13.0-31.2) for those receiving standard therapy, 0% for those receiving an investigational therapy, and 72.6% (95% CI: 57.8-85.7) for the palliative care group. Conclusion: Our data support the feasibility of a rapid precision medicine approach in older patients with previously untreated AML. Patients with AML who elected treatment assigned based upon cytogenetic and molecular alterations in the dominant clone using a novel precision medicine approach had significantly improved overall survival versus those who elected standard of care treatment. Disclosures Levine: Gilead: Consultancy; Prelude Therapeutics: Research Funding; Celgene: Consultancy, Research Funding; Novartis: Consultancy; Isoplexis: Membership on an entity's Board of Directors or advisory committees; Roche: Consultancy, Research Funding; Qiagen: Membership on an entity's Board of Directors or advisory committees; Loxo: Membership on an entity's Board of Directors or advisory committees; Imago Biosciences: Membership on an entity's Board of Directors or advisory committees; C4 Therapeutics: Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria; Lilly: Honoraria. Mims:Abbvie: Membership on an entity's Board of Directors or advisory committees; Agios Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Astellas Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; PTC Therapeutics: Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees. Borate:Novartis: Consultancy; Takeda: Consultancy; Pfizer: Consultancy; Daiichi Sankyo: Consultancy; AbbVie: Consultancy. Stein:Agios: Consultancy, Membership on an entity's Board of Directors or advisory committees; Astellas Pharma US, Inc: Membership on an entity's Board of Directors or advisory committees; Celgene Corporation: Membership on an entity's Board of Directors or advisory committees; PTC Therapeutics: Membership on an entity's Board of Directors or advisory committees; Syros: Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo, Inc.: Membership on an entity's Board of Directors or advisory committees; Bioline: Membership on an entity's Board of Directors or advisory committees; Genentech: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Patel:France Foundation: Honoraria; Dava Oncology: Honoraria; Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Baer:Takeda: Research Funding; Incyte: Research Funding; Kite: Research Funding; Forma: Research Funding; AI Therapeutics: Research Funding; Abbvie: Research Funding; Astellas: Research Funding. Stock:Daiichi: Membership on an entity's Board of Directors or advisory committees; Agios: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees; Research to Practice: Honoraria; UpToDate: Honoraria; Kite, a Gilead Company: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees. Deininger:Pfizer: Consultancy, Honoraria, Research Funding; Ascentage Pharma: Consultancy, Honoraria; TRM: Consultancy; Sangoma: Consultancy; Fusion Pharma: Consultancy; Adelphi: Consultancy; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Humana: Honoraria; Incyte: Honoraria; Novartis: Honoraria; Sangamo: Consultancy; Blueprint: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Blum:Boehringer Ingelheim: Research Funding; Celgene: Research Funding; Astellas,: Research Funding; Xencor: Research Funding; Forma: Research Funding; AmerisourceBergen: Consultancy. Schiller:Amgen: Other, Research Funding; Agios: Research Funding, Speakers Bureau; Celgene: Research Funding, Speakers Bureau; Constellation Pharmaceutical: Research Funding; Daiichi Sankyo: Research Funding; Eli Lilly and Company: Research Funding; FujiFilm: Research Funding; Genzyme: Research Funding; Gilead: Research Funding; Incyte: Research Funding; J&J: Research Funding; Jazz Pharmaceuticals: Honoraria, Research Funding; Karyopharm: Research Funding; Novartis: Research Funding; Onconova: Research Funding; Pfizer Pharmaceuticals: Equity Ownership, Research Funding; Sangamo Therapeutics: Research Funding; Bristol Myer Squibb: Research Funding; Astellas: Research Funding; Biomed Valley Discoveries: Research Funding. Olin:Daiichi Sankyo: Research Funding; Astellas: Research Funding; Genentech: Consultancy, Research Funding; Pfizer: Research Funding; Jazz Pharmaceuticals: Consultancy, Honoraria; Revolution Medicine: Consultancy; AstraZeneca: Research Funding; Clovis: Research Funding; Ignyta: Research Funding; MedImmune: Research Funding; Mirati Therapeutics: Research Funding; Novartis: Research Funding; Spectrum: Research Funding. Foran:Agios: Honoraria, Research Funding. Lin:Pfizer: Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Honoraria. Traer:AbbVie: Consultancy; Agios: Consultancy; Astellas: Consultancy; Daiichi Sankyo: Consultancy; Notable Labs: Equity Ownership. Odenike:AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Incyte: Research Funding; Astra Zeneca: Research Funding; Astex Pharmaceuticals: Research Funding; NS Pharma: Research Funding; Gilead Sciences: Research Funding; Janssen Oncology: Research Funding; Oncotherapy: Research Funding; Agios: Research Funding; CTI/Baxalta: Research Funding. Arellano:Gilead: Consultancy. Vergilio:Roche Holding AG: Equity Ownership; Foundation Medicine: Employment. Brennan:Foundation Medicine: Employment. Vietz:Foundation Medicine: Employment. Druker:ALLCRON: Membership on an entity's Board of Directors or advisory committees; Pfizer: Research Funding; Aileron Therapeutics: #2573, Constructs and cell lines harboring various mutations in TNK2 and PTPN11, licensing fees , Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Patents & Royalties, Research Funding; Burroughs Wellcome Fund: Membership on an entity's Board of Directors or advisory committees; Cepheid: Consultancy, Honoraria; The RUNX1 Research Program: Membership on an entity's Board of Directors or advisory committees; GRAIL: Equity Ownership, Other: former member of Scientific Advisory Board; Patient True Talk: Consultancy; Dana-Farber Cancer Institute (antibody royalty): Patents & Royalties: #2524, antibody royalty; Pfizer: Other: PI or co-investigator on clinical trial(s) funded via contract with OHSU., Research Funding; Merck & Co: Patents & Royalties: Dana-Farber Cancer Institute license #2063, Monoclonal antiphosphotyrosine antibody 4G10, exclusive commercial license to Merck & Co; OHSU (licensing fees): Patents & Royalties: #2573, Constructs and cell lines harboring various mutations in TNK2 and PTPN11, licensing fees ; Amgen: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Aptose Biosciences: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Beta Cat: Membership on an entity's Board of Directors or advisory committees, Other: Stock options; Blueprint Medicines: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Vivid Biosciences: Membership on an entity's Board of Directors or advisory committees, Other: Stock options; Beat AML LLC: Other: Service on joint steering committee; CureOne: Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy; Gilead Sciences: Other: former member of Scientific Advisory Board; ICON: Other: Scientific Founder of Molecular MD, which was acquired by ICON in Feb. 2019; Monojul: Other: former consultant; Novartis: Other: PI or co-investigator on clinical trial(s) funded via contract with OHSU., Patents & Royalties: Patent 6958335, Treatment of Gastrointestinal Stromal Tumors, exclusively licensed to Novartis, Research Funding; Bristol-Myers Squibb: Other: PI or co-investigator on clinical trial(s) funded via contract with OHSU., Research Funding. Byrd:Novartis: Other: Travel Expenses, Speakers Bureau; BeiGene: Research Funding; Pharmacyclics LLC, an AbbVie Company: Other: Travel Expenses, Research Funding, Speakers Bureau; Acerta: Research Funding; Ohio State University: Patents & Royalties: OSU-2S; Genentech: Research Funding; Gilead: Other: Travel Expenses, Research Funding, Speakers Bureau; TG Therapeutics: Other: Travel Expenses, Research Funding, Speakers Bureau; Janssen: Consultancy, Other: Travel Expenses, Research Funding, Speakers Bureau.