Foran, James M.

Background: Less-fit patients with acute myeloid leukemia (AML) or high-risk myelodysplasia (MDS) age 60 years and older constitute the majority of patients with AML/MDS but are not well represented in clinical trials. DNA-methyltransferase inhibitor (HMA) monotherapy (e.g. azacitidine or decitabine) is usual. Overall response rates (ORR) are low; improvement in overall survival relative to supportive care alone is modest, highlighting the critical need for efficient identification of effective novel therapies. Blocking programed cell death protein-1 (PD-1) signaling with nivolumab may increase the sensitivity of AML cells to azacitidine and improve outcomes and is the focus of one arm of the S1612 trial. Signaling through PD-1 contributes to tumor immune evasion and growth in AML [Chen, Cancer Biol Ther 2008]. Increased expression of PD-1 (~40% of AML), is associated with poor HMA response [Ørskov, Oncotarget 2015]. A single center azacitidine/nivolumab non-randomized phase II study in relapsed/refractory AML reported ORR of 33% (23/70), including 22% complete remission/complete remission with incomplete hematologic recovery [Daver, Cancer Discovery 2018]. About 25% of the patients developed grade 2-4 immune toxicities; nivolumab immune-related adverse events led to treatment discontinuation in nearly 1 in 7 patients. Study Design and Methods:The S1612 trial [NCT03092674] is a platform randomized phase II/III clinical trial with a common azacitidine control arm (CA) and two currently active experimental arms (EA). Therapy is intended for community setting: azacitidine/nivolumab; and azacitidine/midostaurin. The innovative design utilizes a phase II go/no-go decision comparing each EA with the CA independently when there are 100 pts/arm and 104 deaths on the EA and CA combined. EAs will proceed to phase III if the null hypothesis (HR=1) is rejected in favor of the EA (15% one-sided alpha). When the two currently active EAs complete phase II accrual, a third EA (decitabine/cytarabine) will open. The CA stays open the entire length of the trial and only concurrently randomized patients will be compared across arms. If an EA proceeds to phase III, 200 additional patients (300 total patients) will be accrued. Phase III analysis occurs 1.5 years after accrual or at 414 deaths (in the respective EA and CA), whichever comes first. The phase III tests the null hypothesis with 4.5% two-sided alpha and 83% power for each EA to detect an improvement in median OS from 10.4 to 15.6 months. Eligible pts are age ≥60 years, newly diagnosed AML with ≥ 20% blasts or myelodysplastic syndrome with excess blasts-2 (MDS-EB-2); deemed by the treating physician unfit for standard cytotoxic chemotherapy; and no prior HMA permitted. Trial in Progress Issues:Between December 2017 and October 2018, 113 patients were screened and 78 randomized to study treatment (median/range age: 75/61-86 years; median/range performance status 1/0-3). Two concerns challenged this trial: 1) required administration of 7-day azacitidine at the enrolling sites created a burden for this population and 2) an early excess grade 5 toxicity signal in the azacitidine/nivolumab arm compared with the control arm. Without a control comparison, this safety signal likely would have been missed. Strategies to address these concerns were developed by the study team. Discussion with the sponsor and US Food and Drug Administration (FDA) focused on allowance of standard-of-care protocol-directed azacitidine administration in the patient's primary care doctor's office rather than at the oncology center. Because of the toxicity concern, the trial was placed on partial clinical hold for further evaluation and possible nivolumab-arm eligibility changes, along with new surveillance and pre-emptive action including prompt steroid initiation for suspected immune-related toxicities. The S1612 trial highlights special concerns when enrolling vulnerable populations onto leukemia clinical trials, and the importance of collaborative strategies including with the FDA to preserve clinical trial integrity for patient benefit. It also demonstrates the efficiency this novel platform design has for therapeutic investigation and, importantly, very early identification of serious toxicity. Updates on accrual and resolution and of these issues will be presented. Disclosures Hay: Kite: Research Funding; Gilead: Research Funding; AbbVie: Research Funding; Janssen: Research Funding; MorphoSys: Research Funding; Seattle Genetics: Research Funding; Takeda: Research Funding; Celgene: Research Funding; Roche: Research Funding; Novartis: Research Funding. Assouline:Janssen: Consultancy, Honoraria, Speakers Bureau; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria, Speakers Bureau; Abbvie: Consultancy, Honoraria. Walter:Pfizer: Consultancy, Research Funding; Race Oncology: Consultancy; New Link Genetics: Consultancy; Agios: Consultancy; Amphivena Therapeutics: Consultancy, Equity Ownership; Seattle Genetics: Research Funding; Aptevo Therapeutics: Consultancy, Research Funding; Argenx BVBA: Consultancy; Astellas: Consultancy; BioLineRx: Consultancy; BiVictriX: Consultancy; Boehringer Ingelheim: Consultancy; Boston Biomedical: Consultancy; Covagen: Consultancy; Daiichi Sankyo: Consultancy; Jazz Pharmaceuticals: Consultancy; Kite Pharma: Consultancy; Amgen: Consultancy. Foran:Agios: Honoraria, Research Funding. Radich:TwinStrand Biosciences: Research Funding; Novartis: Other: RNA Sequencing. Othus:Celgene: Other: Data Safety and Monitoring Committee; Glycomimetics: Other: Data Safety and Monitoring Committee. Erba:Astellas Pharma: Consultancy; Amgen: Consultancy; Amgen: Consultancy; ImmunoGen: Consultancy, Research Funding; Novartis: Consultancy, Research Funding, Speakers Bureau; MacroGenics: Consultancy, Other: Lecture fees, Research Funding; Pfizer: Consultancy; Pfizer: Consultancy; ImmunoGen: Consultancy, Research Funding; Covance: Other: Fees for serving as chair on an independent review board for AbbVie Phase III studies; Astellas Pharma: Consultancy; Covance: Other: Fees for serving as chair on an independent review board for AbbVie Phase III studies; MacroGenics: Consultancy, Other: Lecture fees, Research Funding; AbbVie: Consultancy, Other: Chair, IRC for phase III studies, Research Funding; AbbVie: Consultancy, Other: Chair, IRC for phase III studies, Research Funding; Seattle Genetics: Consultancy; Seattle Genetics: Consultancy; Celgene: Consultancy, Other: chair, AML Registry Scientific Steering Committee, Speakers Bureau; Celgene: Consultancy, Other: chair, AML Registry Scientific Steering Committee, Speakers Bureau; Daiichi Sankyo: Consultancy, Research Funding; Daiichi Sankyo: Consultancy, Research Funding; GlycoMimetics: Consultancy, Other: Chair, data and safety monitoring board, Research Funding; GlycoMimetics: Consultancy, Other: Chair, data and safety monitoring board, Research Funding; Agios: Consultancy, Speakers Bureau; Agios: Consultancy, Speakers Bureau; Incyte: Consultancy, Speakers Bureau; Incyte: Consultancy, Speakers Bureau; Jazz Pharmaceuticals: Consultancy, Speakers Bureau; Jazz Pharmaceuticals: Consultancy, Speakers Bureau; Novartis: Consultancy, Research Funding, Speakers Bureau. Michaelis:Pfizer: Equity Ownership, Research Funding; Incyte: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Novartis: Consultancy; TG Therapeutics: Consultancy, Research Funding; JAZZ: Other: Data Safety Monitoring Board, uncompensated, Research Funding; BMS: Research Funding; Bioline: Research Funding; ASTEX: Research Funding; Janssen: Research Funding; Millenium: Research Funding; Macrogeneics: Research Funding. OffLabel Disclosure: Off label experimental combination therapies in newly diagnosed AML/MDS will be discussed, including nivolumab and azacitidine.

Background: NGS of myeloid mutations is an integral part of AML clinical decision-making. There is currently no information regarding concordance between NGS panels in AML using samples from the same patient across various platforms in different diagnostic laboratories. To study this important question, we analyzed NGS of myeloid mutations in diagnostic samples from The Beat AML Master Trial (BAMT) for newly diagnosed older AML patients, and compared variant calls made between institutional laboratories enrolling the study subject with those made by Foundation Medicine (FM), the central laboratory used for treatment assignment in this precision medicine trial. Methods: We identified newly diagnosed AML patient samples (peripheral blood (PB) and/or bone marrow (BM)) from 2 lead institutions in the BAMT(Ohio State, OSU and Oregon Health and Sciences University, OHSU) that were analyzed by both the institutional and by FM from Nov 15, 2016 to Apr 15, 2019. Samples sent to both laboratories >3 days apart were excluded. Samples were analyzed at the institutional laboratories using their respective NGS mutational panels and by FM using the FoundationOne®Heme(FMH) NGS panel which utilizes capture based sequencing. The OSU NGS assay utilizes sequencing on Illumina MiSeq. The OHSU NGS assay employs semiconductor-based sequencing (Ion Torrent PGM platform). The variant allele frequency (VAF) sensitivity for detection for all 3 laboratories range from 1-2%. We evaluated the ability to identify mutations in 8 genes : FLT3, IDH1/ 2, NPM1, TET2, DNMT3A, WT1 and TP53 used in treatment assignment in theBAMT. A detection cutoff of 2% was used to define the presence or absence of a mutation. Overall, agreement was defined as the number of times the local and central laboratories made the same call divided by the total number of patients. Sensitivity was defined as the number of present calls made locally divided by the number of present calls made centrally, and specificity as the number of absent calls made locally divided by the number of absent calls made centrally. The overall kappa statistic, controlling for institution, provided another measure of agreement between local and central calls, where a value of 1 indicates perfect agreement. Results: 194 patient samples were identified using methods above and analyzed locally at the screening institution (125 at OSU, 69 at OHSU) and centrally at FM. Type of tissue analyzed for variants between local site and FM were 59 PB, 129 BM, and 6 with BM/PB mismatch. Overall agreement in presence/absence calls between local and central results for each of the 8 genes was over 95% (Table 1). There was perfect agreement for NPM1. The sensitivity was above 94% for all genes except TP53 (88.6%) and WT1 (63.6%). Failure to detect a mutation locally was primarily due to reporting of all TP53 variants, including variants of unknown significance (VUS) (5) by FM as agreed upon in the study protocol, detection at low levels below local site sensitivity cutoff (1), detection of variants in a portion of gene not covered at the local site(1)and possible artifact (1). For the WT1 gene, discordance in 5 samples included VUS (3) reported by FM ,a variant detected in a portion of the gene not covered at the local site(1).and difference in leukemic tissue analyzed with mutation not detected by the central laboratory on a PB sample, and present at the institutional lab on a BM sample; affecting the overall agreement and specificity but not sensitivity. Specificity was at least 98% for each of the 8 genes. Finally, most discrepancies in reported mutations in FLT3 (n=2), IDH1 (n=1), IDH2 (n=2), DNMT3A (n=4) and TET2 (n=5) were due to reporting of VUS in one laboratory and not by another. Conclusion: Detection of pathogenic myeloid mutations using orthogonal assays showed a high degree of concordance for genes used in therapeutic assignment on the BAMT.The small number of discordant results, in TP53 and WT1, were attributed to the reporting of VUS. This study illustrates the importance of quality control and standardization as NGS continues to be widely utilized in AML for clinical decision making, with a variety of platforms across multiple laboratories. Our next steps involve evaluating the differences in VAFs reported between local and central laboratories when a given mutation is identified, as well as the potential reasons for observed differences and clinical implications of known pathogenic mutations vs putative VUS. Disclosures Borate: Daiichi Sankyo: Consultancy; AbbVie: Consultancy; Novartis: Consultancy; Takeda: Consultancy; Pfizer: Consultancy. Vergilio:Foundation Medicine: Employment; Roche Holding AG: Equity Ownership. Stein:Novartis: 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; 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; Bioline: Membership on an entity's Board of Directors or advisory committees; Genentech: 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:France Foundation: Honoraria; Dava Oncology: Honoraria; Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Baer:Astellas: Research Funding; Abbvie: Research Funding; AI Therapeutics: Research Funding; Forma: Research Funding; Incyte: Research Funding; Kite: Research Funding; Takeda: Research Funding. Stock:Daiichi: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees; Agios: 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. Schiller:Amgen: Other, Research Funding; Astellas: Research Funding; Biomed Valley Discoveries: Research Funding; Bristol Myer Squibb: Research Funding; 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; Agios: Research Funding, Speakers Bureau. Blum:AmerisourceBergen: Consultancy; Boehringer Ingelheim: Research Funding; Celgene: Research Funding; Astellas,: Research Funding; Xencor: Research Funding; Forma: Research Funding. Kovacsovics:Pfizer: Research Funding; Jazz: Consultancy; Novartis: Research Funding; Abbvie: Research Funding; Amgen: Consultancy, Research Funding. Foran:Agios: Honoraria, Research Funding. Druker:Pfizer: Research Funding; OHSU (licensing fees): Patents & Royalties: #2573, Constructs and cell lines harboring various mutations in TNK2 and PTPN11, licensing fees ; Cepheid: Consultancy, Honoraria; 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; 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; GRAIL: Equity Ownership, Other: former member of Scientific Advisory Board; Patient True Talk: Consultancy; The RUNX1 Research Program: 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; 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; Dana-Farber Cancer Institute (antibody royalty): Patents & Royalties: #2524, antibody royalty; Burroughs Wellcome Fund: Membership on an entity's Board of Directors or advisory committees; Blueprint Medicines: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Patents & Royalties, Research Funding. Byrd:Gilead: Other: Travel Expenses, Research Funding, Speakers Bureau; Genentech: Research Funding; Acerta: Research Funding; TG Therapeutics: Other: Travel Expenses, Research Funding, Speakers Bureau; Novartis: Other: Travel Expenses, Speakers Bureau; Pharmacyclics LLC, an AbbVie Company: Other: Travel Expenses, Research Funding, Speakers Bureau; Janssen: Consultancy, Other: Travel Expenses, Research Funding, Speakers Bureau; BeiGene: Research Funding; Ohio State University: Patents & Royalties: OSU-2S. Levine: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; Celgene: Consultancy, Research Funding; Roche: Consultancy, Research Funding; Loxo: Membership on an entity's Board of Directors or advisory committees; Qiagen: Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria; Prelude Therapeutics: Research Funding; Novartis: Consultancy; Gilead: Consultancy; Lilly: Honoraria; Imago Biosciences: Membership on an entity's Board of Directors or advisory committees. Mims:Jazz 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; Agios Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees.

Background: Patients ≥55 years of age with rel/ref AML who have failed to achieve complete remission (CR) after standard induction & salvage therapies do not routinely undergo allogeneic hematopoietic cell transplantation (HCT) due to inability to receive myeloablative conditioning and lack of efficacy. With the advent of recently approved targeted therapies (e.g. venetoclax, IDH inhibitors) more patients achieve CR, however durable responses in heavily pre-treated patient populations remain unsatisfactory with very few patients being transplanted. The SIERRA (Study of Iomab-B in Elderly Relapsed or Refractory AML) trial is a prospective, randomized, phase 3 trial designed to address this unmet need. We present the preliminary analysis of the first 50% of patients and analyze the proportion of patients who fail standard chemo and targeted therapies that can then successfully undergo HCT with Iomab-B-based conditioning. Study continues to enroll (N=150), primary end-point durable CR of ≥180 days. Methods: Eligible patients are ≥ 55 years with rel/ref AML (≥5% blasts), adequate organ function, and related/unrelated 8/8 HLA-matched donors. Patients are randomized (1:1) to receive Iomab-B followed 12-14 days later by reduced intensity conditioning (fludarabine(FLU)/TBI) and HCT, or to conventional care (CC). CC patients may receive investigator's choice of salvage therapy, including newly approved targeted agents such as venetoclax, IDH Inhibitors and may proceed to standard HCT if they achieve CR. If patients do not achieve CR, the study allows cross-over (CO) to Iomab-B with HCT. Results: Preliminary data are available from the first 75 patients enrolled on the SIERRA trial. Median age of 64 years (range: 55-77). All patients had active measurable disease (Table 1). Patients in this trial were heavily pretreated with 85% failing ≥2 induction therapies and 33% failing targeted therapies. Molecular and cytogenetics was 68% adverse risk. (NCCN, v1.2018) Following therapeutic dose of Iomab-B as a single agent, there was significant reduction of circulating blasts by day 3 (99%, p<0.0001), and peripheral blasts became undetectable by day 8 prior to FLU. All patients transplanted on the Iomab-B arm with data available showed median days to engraftment of ANC at 14 (range: 9-22) and platelets at 16 (range: 4-30) (Table 1). After randomization, 82% (31/38) patients in the CC arm failed salvage therapy and did not proceed to standard HCT. Significantly, 32% (12/38) of these patients received targeted therapy. 73% (8/11) of the patients receiving venetoclax with HMA or cytarabine did not adequately respond and did not proceed to standard HCT, 45% (5/11) crossed over to Iomab-B and received HCT. Following standard chemotherapies, 85% (22/26) were evaluated for CO. In total, 63% (19/30) received Iomab-B and HCT. The most common reason preventing crossover was disease progression. All crossover (Iomab-B) patients showed similar engraftment (Table 1). CC patients showed increased incidence of febrile neutropenia with grade 3 prior to CO evaluation or HCT, compared to Iomab-B patients prior to HCT (CC: 34%, Iomab-B: 8%). Iomab-B administration was generally well-tolerated with no grade 4 and 1 grade 3 infusion reaction. There were no Iomab-B-related deaths or 100 day non-relapse transplant related mortality deaths in patients on the Iomab-B arm (Table 1). Conclusion: 100% of the patients receiving HCT on the Iomab-B arm engrafted, despite a median of 29% BM blasts pre-Iomab-B. 82% of the patients on the CC arm failed to be eligible for standard of care transplant, including a high percentage of those receiving targeted therapies. On the CC arm, 63% of eligible patients crossed over to Iomab-B/HCT with robust engraftment despite a median of 35% BM blasts pre-Iomab-B. The incidence of grade 3 febrile neutropenia was higher in patients treated on the conventional care arm with salvage therapy vs. those treated on the Iomab-B arm prior to HCT. In conclusion, despite advanced age, active disease and heavily pre-treated patients, 68% (50/74) of all patients enrolled in the SIERRA trial were able to undergo HCT after reinduction and targeted conditioning with Iomab-B. These results show significant improvements in the current rates of transplantation in this patient population. This SIERRA trial is currently enrolling. For full study details see www.sierratrial.com or clinicaltrials.gov (NCT02665065). Disclosures Gyurkocza: Actinium Pharmaceuticals: Research Funding. Nath:Astellas: Consultancy; Actinium: Consultancy; Daiichi Sankyo: Consultancy. Stiff:Amgen: Research Funding; Gamida-Cell: Research Funding; Incyte: Research Funding; Unum: Research Funding; Cellectar: Research Funding; Gilead/Kite Pharma: Consultancy, Honoraria, Research Funding. Tomlinson:Actinium Pharmaceuticals, Inc: Other: Travel Support. Abhyankar:Incyte: Speakers Bureau; Therakos: Other: Consulting, Speakers Bureau. Hari:AbbVie: Consultancy, Honoraria; Cell Vault: Equity Ownership; Sanofi: Honoraria, Research Funding; Spectrum: Consultancy, Research Funding; Amgen: Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; BMS: Consultancy, Research Funding; Janssen: Consultancy, Honoraria; Kite: Consultancy, Honoraria. Al-Kadhimi:Seattle Genetics: Other: Stocks; Celldex Biotech: Other: Stocks. Foran:Agios: Honoraria, Research Funding. Orozco:Actinium Pharmaceuticals: Research Funding. Van Besien:Miltenyi Biotec: Research Funding. Sabloff:Celgene: 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; ASTX: Membership on an entity's Board of Directors or advisory committees, Research Funding; Jazz Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; Actinium Pharmaceuticals, Inc: 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; Pfizer Canada: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi Canada: Research Funding. Kebriaei:Pfizer: Honoraria; Kite: Honoraria; Jazz: Consultancy; Amgen: Research Funding; Pfizer: Honoraria; Kite: Honoraria; Jazz: Consultancy; Amgen: Research Funding. Levy:Takeda (Millennium Pharmaceuticals): Consultancy. Lazarus:Adaptive Biotechnologies: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria, Speakers Bureau; Actinium Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Teva Pharmaceuticals: Speakers Bureau; Biosight: Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Consultancy, Honoraria, Speakers Bureau; Novartis: Honoraria, Speakers Bureau; AstraZeneca: Honoraria, Speakers Bureau; Bristol Myers Squibb: Honoraria, Speakers Bureau; Pluristem Therapeutics, Inc: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; CSL Behring: Consultancy; Genentech: Speakers Bureau. Giralt:Novartis: Consultancy; Actinium: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Jazz Pharmaceuticals: Consultancy; Amgen: Consultancy, Research Funding; Kite: Consultancy; Miltenyi: Research Funding; Takeda: Consultancy, Research Funding; Johnson & Johnson: Consultancy, Research Funding; Spectrum Pharmaceuticals: Consultancy. Berger:Actinium Pharmaceuticals, Inc: Employment, Equity Ownership. Reddy:Actinium Pharmaceuticals: Employment. Pagel:Pharmacyclics: Consultancy; AstraZeneca: Consultancy; Gilead Sciences: Consultancy.

Background: Chimeric antigen receptor T-cell (CAR-T) therapy has revolutionized the treatment of relapsed/refractory B-cell lymphoid malignancies. Axicabtagene ciloleucel (axi-cel), an anti-CD19 CAR-T not only targets the malignant B-cell, but can potentially also target and eliminate normal B-cells. This can interfere with the normal B-cell repertoire, compromising host humoral immunity such as decreased titers of common vaccines (DTaP, MMR). To assess if this was a clinically significant problem, we evaluated all recipients of axi-cel at our center between 6/2018 through 7/2019. Patients and methods: For patients who received commercial axi-cel, humoral immunity was evaluated both quantitatively [absolute lymphocyte count (ALC)] as well as qualitatively by serology titers [IgG antibodies (Abs)] for diphtheria, tetanus, pertussis, measles, mumps, and rubella, and total Immunoglobulin G (IgG) levels. Data was collected within 30 days prior to CAR-T infusion, then at day +30 and between days +60 and +100 after CAR-T infusion. Results: We identified 10 patients (males = 5, 50%), with a median age of 49.9 years (range 30-65) who received commercial axi-cel during the study period. Patient characteristics and indications for CAR-T therapy are shown in Table 1; the cohort represented a heavily pre-treated aggressive B-cell lymphoma patient population. Baseline information on antibody (Ab) titers was available in 8 patients. At baseline, all patients had positive tetanus IgG Abs (≥0.01 IU/mL), 7 had positive diphtheria IgG Abs (≥0.01 IU/mL), 6 had positive measles IgG Abs (≥ 1.1 AI), 5 had positive rubella IgG Abs (≥ 1.0 AI), 3 had positive mumps IgG Abs (≥ 1.1 AI). None of the patients had a positive pertussis IgG Abs (≥100 IU/mL). At follow-up, all patients with positive Ab at baseline maintained titers in the positive range at day +30 and between days +60 and +100 (Figure 1). None of the patients demonstrated a clinically meaningful decrease in Abs titers, despite a drop in ALC and IgG levels (table 2). Conclusions: Albeit a small sample size, IgG Ab titers for diphtheria, tetanus, measles, mumps, and rubella did not appear to be affected by axi-cel at a short interval follow-up after infusion (up to day +100). We plan to extend this analysis in a larger cohort with a longer-term prospective follow-up to validate our findings, especially in light of dropping absolute lymphocyte counts and IgG levels. Disclosures Ailawadhi: Celgene: Consultancy; Amgen: Consultancy, Research Funding; Cellectar: Research Funding; Janssen: Consultancy, Research Funding; Takeda: Consultancy; Pharmacyclics: Research Funding. Foran:Agios: Honoraria, Research Funding. Tun:Celgene: Research Funding; Curis: Research Funding; TG Therapeutics: Research Funding; Mundi-pharma: Research Funding; DTRM Biopharma: Research Funding; BMS: Research Funding. Chanan-Khan:Pharmacyclics: Research Funding; Merck: Research Funding; Jansen: Research Funding; Mayo Clinic: Employment; Ascentage: Research Funding; Millennium: Research Funding; AbbVie: Research Funding; Xencor: Research Funding. Kharfan-Dabaja:Daiichi Sankyo: Consultancy; Pharmacyclics: Consultancy.

AbstractBackgroundPatients with acute myeloid leukemia (AML) are surviving longer. There are no data on changes in myocardial mechanics from standard of care low‐dose anthracycline‐based induction chemotherapy in older patients with AML. The aim of this study was to demonstrate the potential utility of strain imaging in detecting early changes in left ventricular function in this patient population after induction chemotherapy.MethodsThirty two patients enrolled in the ECOG‐ACRIN E2906 study (cytarabine and daunorubicin vs clofarabine [Genzyme/Sanofi]) from 2011 to 2014 were evaluated retrospectively. Two‐dimensional transthoracic echocardiography (TTE) imaging with Doppler and two‐dimensional speckle‐tracking echocardiography (2DSTE) using EchoInsight software (Epsilon imaging) were performed before and after induction chemotherapy.ResultsEighteen patients received cytarabine and daunorubicin (7 + 3) and 14 received clofarabine. The clofarabine group was older than the 7 + 3 cohort (67.8 ± 4.0 vs 63.7 ± 3.8, P = .007). There were no other significant differences in cardiac risk factors between groups. The 7 + 3 group had a decrease in average peak systolic global longitudinal (−19.1 ± 2.8 to −17.2 ± 3.0, P = .01) and circumferential strain (−29.4 ± 6.3 to −23.9 ± 4.3, P = .011). These changes were not demonstrated in the clofarabine group and were not associated with a decline in left ventricular ejection fraction (LVEF).ConclusionsIn older AML patients, standard cytarabine and daunorubicin chemotherapy causes early changes in global longitudinal and circumferential strain not seen with clofarabine therapy. These findings demonstrate subclinical left ventricular dysfunction after exposure to low cumulative doses of anthracycline‐based induction chemotherapy and may help us better identify those patients at risk for adverse long‐term cardiovascular outcomes.

Abstract Background: The persistence of detectable MRD in complete remission (CR/CRi - CR with incomplete CBC recovery) has been reported to contribute to inferior outcome in younger AML patients (pts) in retrospective studies, however MRD has not been studied prospectively in older adults (age ≥60 yrs) receiving intensive therapy with curative intent. We performed a planned prospective study of MRD status after AML induction therapy in older adults, integrated into the large multicenter ECOG-ACRIN (E-A) E2906 Phase III trial. Methods Eligible patients age ≥60 yrs with AML were randomized 1:1 to receive either 'Standard' 7&3 (Dauno 60mg/m2) induction, with 2 cycles of intermediate dose Ara-C (1.5g/m2 x 12 doses; 6 doses if age ≥70) consolidation (Arm A); or single agent clofarabine (CLO) induction and consolidation (2 cycles) (Arm B). The design and primary clinical results for E2906 (n=727) have been reported previously (Foran et al, ASH #217a, 2015), demonstrating superior overall survival (OS) with standard therapy despite similar CR/CRi rates using stringent criteria, and similar 30-day induction mortality rates. Submission of diagnostic & remission bone marrow or peripheral blood samples was protocol mandated for prospective MRD assessment, and analysis was performed in the central E-A Leukemia Translational Research Lab (LTL) using 6-color multiparameter flow cytometry. MRD-positive (MRD+) was defined as ≥0.1%. LTL flow cytometric analysis was done blinded to treatment arm and outcome of patients. Only pt samples collected within +/-6 days of CR/CRi confirmation were included in this analysis. Statistical analysis was performed using X2 (categories) and Wilcoxon rank sum (continuous) tests to compare baseline patient and disease characteristics. Log-rank tests and multivariate Cox models stratified by treatment arm and adjusted for patient and disease variable (including WBC, cytogenetics, sex, performance status, secondary AML) were used to examine the MRD effect on OS and disease-free survival (DFS, relapse or death). Results The median follow-up is 47.8 months, and 297 of 685 evaluable patients (43.4%) achieved CR/CRi (Standard 44.6%; CLO 42.0%, p=ns). Remission MRD samples were only available for 147 CR/CRi patients (49.5%), owing to variability in sample viability and AML involvement, collection practices and timing of sample collection at individual sites, and patient/physician decision. 58/147 evaluable CR/CRi patients achieved MRD-negative (MRD-) status (Standard 40.7%, CLO 47.9%, p=0.74). Women (56.9% vs. men 43.1%, p=0.003) were more likely to be MRD-, but there was no other significant difference in MRD status stratified by clinical or disease features. MRD+ status at CR/CRi was associated with significantly inferior OS (p=0.031, Figure 1) and also inferior overall DFS (p=0.02); this was most pronounced for DFS after CLO (Arm B, Figure 2) (p=0.005), but not Standard (Arm A) therapy (p=0.41). The impact of MRD+ was confirmed on multivariate analysis using Cox Model Fitting, for OS: OS for All MRD+ pts, HR 1.64 (95% CI 1.00-2.68) (p=0.05); OS for Standard (Arm A) MRD+ pts, HR 1.06 (95% CI 0.51-2.21) (p=0.87); and OS for CLO (Arm B) MRD+ pts, HR 2.30 (95% CI 1.05-5.06) (p=0.04). There was a similar impact for DFS on multivariate analysis using Cox Model Fitting: DFS for All MRD+ pts, HR 1.86 (95% CI 1.16-2.98) (p=0.01); DFS for Standard (Arm A) MRD+ pts, HR 1.15 (95% CI 0.60-2.19) (p=0.67); and DFS for CLO (Arm B) MRD+ pts, HR 3.45 (95% CI 1.47-8.09) (p=0.004). Post-remission therapy was not stratified by MRD in E2906, and 33% of MRD-evaluable pts underwent allogeneic transplantation (no difference in transplant rate for MRD+ vs. MRD-). Conclusions MRD+ ≥0.1% is common (60.5%) after induction therapy in older adults & is significantly associated with inferior OS and DFS in 1st CR/CRi. However we observed excellent outcomes for MRD- pts in first CR/CRi regardless of induction regimen or post-remission therapy used. MRD+ pts in CR/CRi who went on to receive CLO consolidation had significantly poorer outcomes than those who went on to receive intermediate dose Ara-C consolidation. This observation differs strikingly from younger AML, and suggests that intensified Ara-C may abrogate the adverse impact of MRD in older pts in CR. These results strongly support incorporation of centralized MRD at the time of remission into future studies to guide optimal post-remission strategies in older pts with AML. Disclosures Foran: Agios: Research Funding; Xencor, Inc.: Research Funding. Lazarus:Pluristem Ltd.: Consultancy. Altman:Bayer: Other: payment to the institution to conduct clinical trial work; Pfizer: Other: payment to the institution to conduct clinical trial work; Boeringer Ingelheim: Other: payment to the institution to conduct clinical trial work; Epizyme: Other: payment to the institution to conduct clinical trial work; Janssen Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Immune Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Cyclacel: Other: payment to the institution to conduct clinical trial work; Incyte: Other: payment to the institution to conduct clinical trial work; GSK: Other: payment to the institution to conduct clinical trial work; Agios: Other: Payment to the institution to conduct the trial ; Astellas Pharma: Other; Celgene: Membership on an entity's Board of Directors or advisory committees, Other: payment to the institution to conduct clinical trial work; BMS: Membership on an entity's Board of Directors or advisory committees; Syros: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Ariad: Other: payment to the institution to conduct clinical trial work; FujiFilm: Other: payment to the institution to conduct clinical trial work; Genetech: Other: Payment to the institution to conduct clinical trial work; Celator: Other: payment to the institution to conduct clinical trial work. Al-Kali:Novartis: Research Funding. Pratz:Millenium/Takeda: Research Funding; Agios: Research Funding; AbbVie: Consultancy, Research Funding; Astellas: Consultancy, Research Funding; Boston Scientific: Consultancy. Powell:Rafael Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees. Tallman:ADC Therapeutics: Research Funding; BioSight: Other: Advisory board; Daiichi-Sankyo: Other: Advisory board; Orsenix: Other: Advisory board; AROG: Research Funding; AbbVie: Research Funding; Cellerant: Research Funding.

Abstract Background: We previously demonstrated that putative clinical epidemiologic exposures associated with leukemia risk are prevalent among AML patients, and some are associated with unique cytogenetic risk group and with clinical phenotype (Finn, Cancer Epidemiol, 2015). Herein, we studied genome-wide DNA methylation in a cohort of AML patients to evaluate the association of individual hyper- and hypo-methylated CpG sites with epidemiologic exposures and overall survival. Methods: The Mayo Clinic AML Epidemiology Cohort is a highly annotated retrospective case series of 295 consecutive patients (pts) with AML diagnosed and treated at Mayo Clinic Florida and Arizona, with central cytogenetics performed in all cases. The prevalence of clinical epidemiologic exposures, past medical and family history as well as medication use and lifestyle was systematically obtained. After IRB approval, we interrogated the cytogenetic database and successfully obtained leukemia DNA from available remnant diagnostic cytogenetic cell pellets in a cohort of 148 AML patients in the Mayo epidemiology case series and performed an assessment of genome-wide DNA methylation using the Infinium HumanMethylation450K BeadChip. Samples were processed using the R Bioconductor package 'minfi' using Subset Within Array Quantile Normalization (PMID: 22703947). Individual CpGs that did not reach a detection p-value of <0.05 were filtered out. An internal control was included on each array to control for significant batch effects. To determine differential methylation status of 473,864 individual CpG sites (after exclusion of 11,648 that did not pass detection p-value QC), CpG sites with low interpatient variability, a standard deviation <0.05 of methylation values, and an interquartile range <0.05 of methylation values and X/Y chromosome probes were excluded from analysis. Epidemiologic and important clinical variables occurring in at least 10 pts or previously-identified as of unique interest but in fewer than 10 pts were evaluated, including sex, BMI, performance status and comorbidities, tobacco and alcohol use, family history of hematologic malignancy, medications of interest, history of toxin exposure, and history of immunosuppression and/or solid organ transplant or of secondary and therapy-related AML (t-AML). Associations of differential hypo or hypermethylation at 281,259 CpG sites with epidemiologic exposures/clinical variables were evaluated using Spearman's test of correlation (continuous or ordinal exposures), a Wilcoxon rank sum test (dichotomous exposures), or a Kruskal-Wallis rank sum test (multi-category exposures). A Bonferroni correction was applied for multiple testing, after which p <1.8 x 10-7 was considered as significant. To reduce the likelihood of false-negative findings, we additionally considered p <5 x 10-6 as indicating suggestive evidence of an association. CpG sites and associated gene and function was determined using Illumina manifest file & www.ncbi.nlm.nih.gov/gene. Results: Statistically significant associations (p <1.8 x 10-7) with individual epidemiologic and clinical exposures were identified for 109 unique CpG sites, corresponding to differential methylation in the genes listed in Table. Specifically, obesity (predominantly hypomethylation), specific cytogenetic lesions and risk group, and gender were highly significantly associated with unique CpG methylation status, but not smoking, toxin exposure, family history, comorbidity or performance status, secondary or t-AML, immunosuppression, medication use, of family history in the analysis. A further 353 unique CpG sites had defined suggestive associations (ongoing analysis). We also identified 8 additional CpG sites where differential methylation was associated with overall survival (p <5 x 10-6, Table). Conclusion: Obesity, cytogenetic lesions, and sex are associated with differential methylation of unique CpG sites at AML diagnosis, using stringent univariate statistical criteria. Significant CpG sites were identified in genes previously linked to AML biology and prognosis (DOCK6, HOXB3, MIR10A, FOXN3/CHES1, GPX1, MYST2/KAT7, PTPRD), but some represent novel findings in AML. These preliminary results suggest an association of some AML risk factors and clinical variables with unique gene methylation and will undergo validation in a prospective AML epidemiology dataset. Disclosures Cerhan: Jannsen: Other: Scientific Advisory Board; Nanostring: Research Funding; Celgene: Research Funding. Foran:Agios: Research Funding; Xencor, Inc.: Research Funding.

Abstract Background: Blasts and leukemic stem cells of acute myeloid leukemia (AML) as well as several other hematologic malignancies express CD123, potentially providing a target for novel therapies. XmAb14045 (also known as SQZ622) is a potent bispecific antibody targeting both CD123 and CD3 that stimulates targeted T cell-mediated killing of CD123-expressing cells, regardless of T cell antigen specificity. It is a full-length immunoglobulin molecule designed to be dosed intermittently, in contrast to smaller constructs that are referred to as "DART" or "BiTE" bispecific antibodies that require a continuous infusion. Methods: Patients with relapsed or refractory AML, B cell acute lymphoblastic leukemia (B-ALL), blast phase chronic myelogenous leukemia, or blastic plasmacytoid dendritic cell neoplasm were eligible to enroll on this first-in-human, multicenter, open-label phase 1 dose-escalation study (XmAb14045-01) with standard 3+3 design. The primary objective was to estimate the maximum tolerated dose (MTD) or recommended dose and schedule of XmAb14045. Secondary objectives included safety, preliminary antileukemic activity, and pharmacokinetics/pharmacodynamics of XmAb14045. Treatment was administered weekly in 28 day cycles, using a weight-based dose with a single dose level in Part A and, in Part B, an initial priming dose on Day 1 followed by an escalated dose on subsequent weeks. Premedication to prevent cytokine release syndrome (CRS) was instituted as needed and included a steroid, acetaminophen, and diphenhydramine. Patients were premedicated at all XmAb14045 doses ≥0.075 µg/kg. Therapy was continued for as long as tolerated and there was continuing evidence of therapeutic benefit in the opinion of the investigator. Treatment response was assessed by the 2017 European LeukemiaNet (ELN) criteria after Cycle 1 and after each odd-numbered cycle. CRS was graded using the CRS revised grading system (Lee et al., Blood, 2014). Results: At data cut-off, 64 patients have been treated to date, 63 with relapsed/refractory AML and 1 with B-ALL. Patients had a median age of 61 years and were heavily pretreated (median of 3 prior therapies [range 1-8], including 19 [30%] who had undergone prior allogeneic stem cell transplantation). The recommended dose for Part A was 1.3 µg/kg after a single dose-limiting toxicity of Grade 4 CRS at 2.3 µg/kg; no MTD has been identified. CRS or its component symptoms was the most common treatment-emergent adverse event (TEAE). CRS episodes began within approximately 1-4 hours of the start of drug infusion and occurred in 49 of 64 patients (77%). Seven patients (11%) developed Grade ≥3 CRS, the majority of these on the first dose. There were no CRS-related deaths. Excluding CRS-related events, additional TEAEs occurring in >10% of patients included fatigue (31%), febrile neutropenia (30%), peripheral edema (30%), cough (23%), elevated hepatic transaminases (19%; all recovered without sequelae), pneumonia (17%), stomatitis (14%), hyperglycemia (13%), and sepsis (11%). No myelosuppression requiring dose modification or evidence of tumor lysis syndrome was seen. In Part A, single agent antileukemic activity was documented with a best response of CR (2) or CRi (1) in 3/13 AML patients (CR/CRi rate 23%) treated at the two highest dose levels studied to date (1.3 and 2.3 µg/kg weekly); no CR, CRi, or morphologic leukemia-free state (MLFS) responses were seen at lower doses. Antileukemic activity occurred quickly; all responders had achieved at least an MLFS response after 4 doses (1 cycle). Two responders were bridged to stem cell transplantation, and the third was ineligible for medical reasons but remains in remission at 14+ weeks after initiating therapy. Conclusions: XmAb14045 demonstrated evidence of antileukemic activity in heavily pretreated patients with relapsed/refractory AML treated in Part A at the 1.3 and 2.3 µg/kg doses administered once weekly, with a 23% CR/CRi rate. CRS was the most common toxicity but was generally manageable with premedications. The study is ongoing with further optimization of dose, schedule, and premedication regimen for CRS anticipated during accrual to dose escalation cohorts in Part B. ClinicalTrials.gov Identifier: NCT02730312 Disclosures Ravandi: Xencor: Research Funding; Abbvie: Research Funding; Amgen: Honoraria, Research Funding, Speakers Bureau; Sunesis: Honoraria; Astellas Pharmaceuticals: Consultancy, Honoraria; Abbvie: Research Funding; Seattle Genetics: Research Funding; Macrogenix: Honoraria, Research Funding; Jazz: Honoraria; Sunesis: Honoraria; Seattle Genetics: Research Funding; Bristol-Myers Squibb: Research Funding; Astellas Pharmaceuticals: Consultancy, Honoraria; Orsenix: Honoraria; Xencor: Research Funding; Orsenix: Honoraria; Jazz: Honoraria; Bristol-Myers Squibb: Research Funding; Amgen: Honoraria, Research Funding, Speakers Bureau; Macrogenix: Honoraria, Research Funding. Foran:Xencor, Inc.: Research Funding; Agios: Research Funding. Stock:Jazz Pharmaceuticals: Consultancy. Mawad:Swedish Cancer Institute: Employment. Blum:Astellas: Consultancy; Pfizer: Consultancy; Boehringer Ingelheim: Research Funding; Forma: Research Funding; Xencor: Research Funding; Tolero: Research Funding. Saville:Xencor, Inc.: Employment, Equity Ownership. Johnson:Xencor, Inc.: Employment, Equity Ownership. Vanasse:Novartis: Employment, Equity Ownership. Ly:Xencor, Inc.: Employment, Equity Ownership. Mims:Novartis: Consultancy; Agios Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; Abbvie Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees.

Abstract Introduction: Primary refractory and early relapsed acute myeloid leukemia (RR-AML) continue to pose a therapeutic challenge. Salvage therapy treatment regimens for refractory and relapsed disease are not standardized but include the commonly-used mitoxantrone, etoposide, and cytarabine (MEC) and cladribine, cytarabine, filgrastim, and mitoxantrone (CLAG-M). Previous studies have suggested a potential benefit of CLAG-M, and therefore we performed an analysis of consecutive patients selected to receive either CLAG-M or MEC as salvage therapy for RR-AML. Methods: The study included 150 consecutive patients with RR-AML who received either CLAG-M or MEC between 09/01/2009 and 12/31/2017. Patients were identified through a pharmacy database based on use of mitoxantrone. Baseline disease and patient-related characteristics and clinical outcomes including allogeneic transplantation (ASCT) were obtained by systematic review of EMR. Overall survival (OS) and progression free survival (PFS) were estimated according to the Kaplan Meier method and log-rank test was used to compare outcomes between patients who received either of the two regimens. Results: There were 150 consecutive treated patients with RR-AML included in this analysis, 34 patients received CLAG-M and 116 patients received MEC. The median age was 57 years (18-76), and, and 52% were male. Forty-seven (31%) were treated for early relapsed disease (<6 months after successful induction), 17% (>6 months after induction), and the remainder had primary refractory disease (mean number of induction regimens was 1.8, range 1-6). AML risk was defined by cytogenetic criteria. There were a predominance of intermediate-risk subtypes at 47% (71/150) and followed by high-risk at 37% (55/150). Overall CR/CRi rates for CLAG-M and MEC were 74% (23/31) and 58% (63/108) in patients eligible for analysis (p=0.18). The median follow-up from relapse was 23.5 months (1-76). The median OS was 9.5 months for CLAG-M and 10.0 months for MEC (HR=0.88, 95%CI=0.54-1.41, p=0.59). In total, 76 patients (51%) were able to proceed to ASCT following salvage therapy with either CLAG-M or MEC. Among transplant recipients 56% (19/34) and 49% (57/116) were treated with CLAG-M and MEC, respectively. Median OS after ASCT was 13.0 months for CLAG-M and 31.0 months for MEC (HR=1.76, 95%CI=0.87-3.56, p=0.12). The median OS for refractory AML was 13.0 and 66.0 months for CLAG-M and MEC recipients, respectively (HR=0.92, 95%CI=0.46-1.84, p=0.24). Median OS for those with early relapse was 12.0 months for CLAG-M and 10.0 months for MEC (HR=0.69, 95%CI=0.22-2.11, p=0.51). Lastly, among those who had late relapse, median OS was 9.0 and 48.0 months for CLAG-M and MEC, respectively (HR=17.6, 95%CI=1.57-198, p<0.001). A univariate analysis was performed to investigate the impact of factors associated with OS, including treatment, age, gender, whether they proceeded to ASCT, cytogenetic risk type, and donor source. ASCT was associated with significant improvement in both PFS (HR=0.24, 95%CI=0.16- 0.37, p<0.001) and OS (HR=0.26, 95%CI=0.17-0.40, p<0.001) in this cohort. Age greater than 65 was associated with worse PFS (HR=1.02, 95%CI=1.00-1.03, p=0.04) but not OS (HR=1.01, 95%CI=1.00-1.03, p=0.06) after controlling for other variables including the impact of ASCT. Discussion: Despite a lower 30-day induction mortality we did not identify significant differences in outcomes among patients selected to receive CLAG-M vs. MEC. There was a statistically significant improvement in survival in patients who had late relapses and were treated with MEC, and a trend towards improvement in OS of those treated with MEC who proceeded to ASCT. As expected, ASCT was associated with significant improvement in OS in this cohort, and our results strongly support the use of ASCT as consolidation of remission after relapse for AML. Our data suggests that MEC may be a superior regimen, in particular including those with late relapse. Figure. Figure. Disclosures Foran: Agios: Research Funding; Xencor, Inc.: Research Funding. Al-Kali:Novartis: Research Funding. Palmer:Novartis: Research Funding.

Abstract Introduction: The preferred post-remission therapy for older patients (pts) with AML remains uncertain. We compared outcomes for older AML pts in CR1 receiving HCT reported to the CIBMTR to older AML pts achieving CR1 on National Clinical Trials Network induction and non-HCT consolidation therapy (CT) trials. Methods: This study focused on pts 60-75 years of age treated between 2004 to 2013. CT pts (n=211) underwent induction and consolidation on Alliance for Clinical Trials in Oncology, ECOG-ACRIN or SWOG clinical trials for initial therapy for newly diagnosed AML; the CIBMTR provided data for HCT pts (n=431). CT patients received at least one cycle of CT on study and were excluded if HCT occurred at any time. Time to event started at CR1 and pts entered at CT or HCT, respectively, using left-truncation to account for differential entry times. Results: For the CT cohort, first consolidation included standard therapy (e.g., cytarabine or a hypomethylating agent) and additional study drug (e.g., bortezomib, dasatinib, sorafenib, and Zosuquidar, gemtuzumab) or tipifarnib alone. Among HCT pts, the donor was a HLA-matched sibling or unrelated donor (URD) in 66% and the others were partially HLA-matched/mismatched URD (10%) or cord blood (24%). HCT pts were younger and more frequently had high-risk AML (high WBC, secondary AML and unfavorable cytogenetics) (Table). The median time from CR1 to HCT and CT was 3.2 and 0.5 months, respectively. Allogeneic HCT showed worse overall survival (OS) (HR=1.52, p=0.02) prior to 9 months and better OS thereafter (HR= 0.53, p <0.0001) relative to CT (figure 1A). Treatment-related mortality (TRM) was worse after HCT in the first 9 months (HR=2.8, CI: 1.5 -5.2, p=.0009), while relapse was less frequent beyond 9 months after treatment (HR = 0.42, CI: 0.29 to 0.61, p<.0001). Despite higher early TRM, HCT recipients went on to manifest superior OS [5 year OS: HCT 29% (24-34%), CT 13.8% (9 -22%)] (Figure 1A). The benefit of HCT for survival after 9 months was more prominent in those with unfavorable cytogenetics (Figure 1B). Multivariate analysis for OS showed no statistically significant effect of age or performance status, while unfavorable cytogenetics were detrimental (HR=1.74, p<.0001). Conclusions. Allogeneic HCT led to heightened early risks from TRM, but resulted in superior long-term survival in older AML pts receiving HCT relative to CT by reducing relapse. Efforts to attenuate early TRM after allogeneic HCT may further improve HCT outcomes for older pts. Disclosures Ustun: novartis: Speakers Bureau. Attar:Agios: Employment, Equity Ownership. Larson:Pfizer: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; BristolMyers Squibb: Consultancy, Research Funding; Ariad/Takeda: Consultancy, Research Funding. Roboz:Roche/Genentech: Consultancy; Eisai: Consultancy; Cellectis: Research Funding; Aphivena Therapeutics: Consultancy; Sandoz: Consultancy; Janssen Pharmaceuticals: Consultancy; Otsuka: Consultancy; Jazz Pharmaceuticals: Consultancy; Sandoz: Consultancy; AbbVie: Consultancy; Celltrion: Consultancy; Cellectis: Research Funding; Eisai: Consultancy; Astex Pharmaceuticals: Consultancy; Argenx: Consultancy; Pfizer: Consultancy; Celgene Corporation: Consultancy; Novartis: Consultancy; Jazz Pharmaceuticals: Consultancy; Bayer: Consultancy; Bayer: Consultancy; Roche/Genentech: Consultancy; Orsenix: Consultancy; Astex Pharmaceuticals: Consultancy; Celgene Corporation: Consultancy; Daiichi Sankyo: Consultancy; Pfizer: Consultancy; Janssen Pharmaceuticals: Consultancy; Otsuka: Consultancy; Orsenix: Consultancy; Daiichi Sankyo: Consultancy; Celltrion: Consultancy; Novartis: Consultancy; Aphivena Therapeutics: Consultancy; Argenx: Consultancy; AbbVie: Consultancy. Uy:GlycoMimetics: Consultancy; Curis: Consultancy. Stone:Fujifilm: Consultancy; Ono: Consultancy; Orsenix: Consultancy; Otsuka: Consultancy; Agios: Consultancy, Research Funding; AbbVie: Consultancy; Argenx: Other: Data and Safety Monitoring Board; Celgene: Consultancy, Other: Data and Safety Monitoring Board, Steering Committee; Arog: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Jazz: Consultancy; Astellas: Consultancy; Merck: Consultancy; Pfizer: Consultancy; Sumitomo: Consultancy; Amgen: Consultancy; Cornerstone: Consultancy. Foran:Agios: Research Funding; Xencor, Inc.: Research Funding. Weisdorf:Seattle Genetics: Consultancy; Equillium: Consultancy; FATE: Consultancy; SL Behring: Consultancy; Pharmacyclics: Consultancy.