ALBERT

Description: Abstract 1626 Poster Board I-652 Introduction Familial Platelet Disorder with Propensity to Acute Myelogenous Leukemia (FPD/AML; OMIM 601399) is a rare disorder with an autosomal dominant inheritance pattern characterized by varying degrees of thrombocytopenia, clinical bleeding due to platelet dysfunction, and an increased risk of developing myeloid malignancy. To date, twenty-six families with this disorder have been described and all carry germline RUNX1 mutations as the causative genetic abnormality. The spectrum of RUNX1 mutations includes point mutations within the RUNT domain and frameshift and termination mutations throughout the body of the gene. Here we report identification of a new family with FPD with a novel nonsense mutation resulting in premature protein termination at amino acid 388. Patients and Methods Our four generation pedigree includes a mother (II:4) diagnosed with dysplasia and normal karyotype acute myeloid leukemia now in remission after a matched sibling allogeneic stem cell transplant, and her daughter (III:2) with thrombocytopenia since childhood, excessive bleeding with childbirth, and 5q- syndrome diagnosed at 37 years old. Genomic DNA was obtained from all available family members, and RUNX1 cDNA (transcription variants a through c) was sequenced. In addition, RUNX1 cDNA was analyzed for second mutations in bone marrow samples from both patients at the time of diagnosis of their initial bone marrow malignancy. Results RUNX1 sequencing of germline DNA revealed heterozygosity for a novel nonsense mutation in exon 8 (c.1163C〉A), which is predicted to result in premature protein truncation (p.Ser388X). Full sequencing of RUNX1 cDNA from II:4's AML does not show any secondary mutations. Our current efforts include full sequencing of RUNX1 cDNA from III:2's bone marrow malignancy as well as functional studies of the truncated protein. Conclusions We have identified a novel 3' RUNX1 mutation within exon 8, which is predicted to result in premature protein truncation at amino acid 388. To date, this is the most distal mutation identified in an FPD/AML pedigree. The identification of this mutation suggests that the last 100 amino acids, which are known to contain the RUNX1 inhibition domain, contribute an essential function. Further characterization of this RUNX1 mutation and its encoded truncated protein may yield insight into RUNX1's role in leukemogenesis in FPD and de novo AML. Disclosures No relevant conflicts of interest to declare.

Description: Background: Aurora kinases play essential roles in regulating cell division, and increased expression has been noted in myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). We previously conducted a phase I study of alisertib combined with "7+3" induction chemotherapy in untreated patients with AML, and found the combination to have an adverse event profile similar to 7+3 alone, with promising efficacy, particularly for patients with high-risk disease, such as those who were older, with high-risk molecular features, or with secondary AML. These patients collectively have a historically grim prognosis, with an approximate rate of remission, in trials, of 45%. CPX-351, a liposomal daunorubicin-cytarabine product, was recently approved for use in secondary AML after it was demonstrated to be superior to 7+3 induction, with a median survival of 9.6 months versus 5.9 months among older patients, in a phase 3 trial. We recently completed accrual to a phase II study of alisertib plus induction chemotherapy in patients with untreated, high-risk AML. Methods: Patients were eligible if they had AML defined by WHO 2016 and either an adverse-risk karyotype (European Leukemia Net Guidelines), secondary (post-MDS/MPN) AML, therapy-related AML, or age ≥ 65 vears. We used a Simon two-stage design, assuming a null composite remission rate (complete remission [CR] and CR with incomplete count recovery [CRi]) of 45%. Patients could be enrolled prior to cytogenetic classification, but those without adverse-risk karyotype who lacked other eligibility criteria were removed before day 8 and replaced. All patients received continuous infusion cytarabine 100mg/m2 on days 1-7 [D1-7] and idarubicin 12mg/m2 [or daunorubicin 60mg/m2] D1-3 (7+3). On D8 through D15, alisertib at 30mg BID orally (PO) was administered. All underwent a mid-induction marrow biopsy to assess for residual disease, which if present, was treated with 5+2 re-induction without alisertib. Following remission, patients could receive up to 4 consolidation cycles with cytarabine (3g/m2 BID D1,3,5 for age

Description: Introduction Effective therapies for R/R AML remain limited. MEK or MDM2 inhibition can downregulate MCL1, overcoming resistance to BCL2 inhibition. Preclinical synergy was seen when combining BCL2 inhibitor Ven with MEK inhibitor cobimetinib (cobi) or MDM2 inhibitor idasa (Han et al. ASH 2016; Pan et al. Cancer Cell 2017), supporting clinical evaluation in AML. Preliminary data in a Phase Ib dose-escalation study (NCT02670044) evaluating Ven+cobi/idasa in R/R AML suggested both combinations were tolerable (Daver et al. ASH 2017). However, Ven+cobi was closed due to limited clinical activity. Here we present data for additional pts, longer follow-up and biomarker analyses for Ven+idasa. Methods This ongoing, open-label, multicenter study evaluates safety, tolerability and efficacy of Ven+idasa in R/R AML or secondary AML previously treated for an antecedent hematologic disease. Pts 〉60 yrs of age and ineligible for cytotoxic therapy/allogeneic stem cell transplant were enrolled. A 2-dimensional dose escalation was used to establish the maximum tolerated dose: pts received doses of Ven orally (PO) daily (400mg or 600mg) + idasa PO daily on Days 1-5 (150mg, 200mg, or 400mg) in 28-day cycles. Plasma samples were taken for PK analysis at Cycles 1 and 2 Days 1 and 5, and Cycle 4 Day 1. BCL2, BCLxL and MCL1 status and minimal residual disease (MRD) were assayed centrally at Covance Laboratories using multicolor flow cytometry. Mutation (mut) sequencing was performed by Foundation Medicine using FoundationOne Heme at screening and from last bone marrow collected on study. Results As of April 6 2018, 34 pts received Ven+idasa across all dose cohorts (Table 1). Median age: 74 (range 64-93) yrs; median prior therapies: 1 (range 1-4); ECOG performance status 2: 18%; refractory: 56%; secondary AML: 53%; adverse cytogenetics: 27%. Pre-therapy mut data were available for 32 pts; most common muts were RUNX1 14 (41%), ASXL1 11 (32%), SRSF2 11 (32%). Other significant pre-therapy muts: TP53 6 (18%), IDH2 7 (21%), IDH1 1 (3%), FLT3 4 (13%). The most common adverse events (AEs) were diarrhea (88%) and nausea (71%); the most common grade (Gr) ≥3 AEs were neutropenia (32%), febrile neutropenia (32%), thrombocytopenia (29%; Table 2). After 2 cases of Gr 3 diarrhea in the Ven 600mg cohorts, mandatory prophylaxis was implemented; no further cases of Gr ≥3 diarrhea were seen in the following 10 pts. Laboratory tumor lysis syndrome occurred in 3 pts (9%); none required treatment discontinuation. There was no apparent PK drug-drug interaction between Ven and idasa. PK was dose-proportional over the ranges tested for Ven and idasa. The recommended Phase II dose (RP2D) has not been identified yet. Across all dose cohorts, 30/34 pts were response-evaluable; the remaining 4 were still on study treatment without post-baseline response assessment. The anti-leukemic response rate (CR+CRp+CRi+MLFS+PR) was 37% (11/30). Across the 2 Ven 600mg cohorts, which are being considered for RP2D, the anti-leukemic response rate was 9/18 (50%) (Table 1, Figure 1). MRD negativity (

Description: ABSTRACT: The nucleophosmin-1 (NPM1) mutation represents the most common genetic lesion (30-35%) in adult acute myeloid leukemia (AML) with the mutation resulting in the cytoplasmic delocalization of the NPM protein (NPMc+, most commonly mutation type A, c.860_863dupTCTG). Outside of conventional chemotherapy, treatment options for those with relapsed disease are extremely limited. We have previously discovered that leukemic cells expressing NPMc+ are preferentially sensitive to the cytotoxic effects of the first generation proteasome inhibitor, bortezomib, as result of the induction of superoxide in these cells (Huang M, et al., Leukemia, 2013). However, bortezomib has demonstrated only modest anti-leukemic activity as a single agent in early phase clinical trials that have included primarily heavily pretreated patients not stratified according to mutational genotype. In addition, the high incidence of clinically significant peripheral neuropathy in these studies led to early discontinuation of treatment. MLN9708 (Ixazomib) is a novel second generation proteasome inhibitor that is orally bioavailable and has shown promising activity and improved tolerability in early phase clinical trials in lymphoma and in multiple myeloma, where it is currently in a Phase III clinical trial. The efficacy of MLN9708 in relapsed patients with AML has not yet been examined. We have investigated the in vitro effects of MLN9708 on the cytotoxicity, generation of reactive oxygen species (ROS), and cellular glutathione in both cultured NPMc+ AML cell lines and primary leukemic samples. Cultured OCI-AML3 cells (human AML cell line featuring the NPMc+ mutation) were approximately 50-fold more sensitive to MLN9708 with a mean half inhibitory concentrations (IC50 ± SD) of 67 nM ± 1.83 nM at 24 hours than were an AML cell line (THP-1) expressing wild type NPM1. Knockdown of both NPM1/NPMc+ by inducible NPM1 shRNA expression significantly attenuated the MLN9708-mediated cytotoxicity, as determined by MTS colorimetric and flow cytometric apoptosis assays. As with bortezomib, MLN9708 treatment at 75 nM induced a 2.1-fold (p 〈 0.002) increase in superoxide-specific DHE (PE)-derived fluorescence as compared to controls. Pre-incubation of cells with 25 mM N-acetylcysteine, a ROS scavenger, dramatically reduced cytotoxicity, strongly implicating the generation of ROS in the mechanism of MLN9708-induced cytotoxicity. Knockdown of NPM1/ NPMc+ expression resulted in an increase of glutathione levels of 2.6-fold (p 〈 0.04) in untreated cells, and 2.3-fold (p 〈 0.005) and 2.9-fold (p 〈 0.004) after a 22 hour incubation with MLN9708 at pharmacologically achievable doses of 75 nM and 150 nM, respectively (Figure 1). In addition, a concomitant 4-fold reduction (p 〈 0.04) in the NADP+/NADPH ratio was observed in the NPM1/NPMc+ depleted OCI-AML3 cells. In vitro apoptosis assays of primary leukemic blasts isolated from five patients with relapsed NPMc+ AML showed an IC50 for MLN9708 ranging from 49.963-467.487nM (183.8 nM ± 176.8 nM). Based on these promising in vitro studies, a Phase 2 clinical trial of single-agent oral MLN9708 (clinicaltrials.gov identifier: NCT02030405) has been initiated for patients with relapsed or refractory NPMc+ AML. We conclude that the expression of NPMc+ renders AML cells more susceptible to MLN9708 toxicity and that this effect results at least in part from the generation of superoxide. Lower glutathione levels in NPMc+ expressing cells suggests an underlying defect in the antioxidant defense pathway. Demonstration of the sensitivity of NPMc+ AML cells to MLN9708 as a single agent may serve as a platform for the development of novel combination strategies with this drug. Acknowledgments: Research was facilitated by the ASH Clinical Research Training Institute and AACR/ASCO Clinical Cancer Research training program. J.S.G is funded by the Leukemia & Lymphoma Society Career Development Award and ASCO YIA award through a grant supported by Mr. Aaron Sasson. J.S.G. is further supported by the Stanford Hematology Fellowship Program. Figure 1 Effect of NPM1/NPMc+ depletion in OCI-AML3 cells on intracellular glutathione levels Figure 1. Effect of NPM1/NPMc+ depletion in OCI-AML3 cells on intracellular glutathione levels Disclosures Off Label Use: MLN9708 is an investigational compound by Millennium Pharmaceuticals, Inc. (MPI). Through an MTA we have secured the compound for in vitro analysis. This data has led to a clinical trial and drug for that study is supplied by MPI.. Medeiros:Agios: Consulting - Ad board Other.

Description: Introduction: Acute undifferentiated leukemia (AUL) is a rare type of acute leukemia that shows no evidence of differentiation along any lineage. Clinical, immunophenotypic and genetic data is limited: the largest study to date reported 16 AUL cases but did not use the current WHO classification and included limited genetic data on 5 cases (Ann Hematol 2013 92:747-758). Moreover, it is uncertain if AUL is biologically distinct from acute myeloid leukemia with minimal differentiation (AML MD), which also shows limited myeloid marker expression and has been reported to have a poor prognosis. Methods: A total of 95 cases (36 AUL cases 59 AML MD) were identified from pathology databases of eight academic institutions with available diagnostic flow cytometric data, cytogenetic findings, and clinical data by searching for diagnoses of "AUL" or "AML MD". Diagnosis of AUL required absence of any lineage-defining markers including MPO, CD19 and CD3. Using the WHO classification, diagnosis of AML with MD required expression of at least 2 myeloid markers (CD117, CD13 or CD33), absence of myeloid maturation (CD15) or monocytic markers (CD64, CD11b, lysozyme or non-specific esterase). Next generation sequencing with extensive mutational panel data was available in 78 cases. Outcome analysis for overall survival (OS) and relapse-free survival (RFS) and were performed using Kaplan Meier and log rank test for patients who received induction chemotherapy. Results: Based on cytogenetic abnormalities (N=27) or history of MDS (N=2), according to the 2016 WHO Classification, 28 cases (6 AUL and 22 AML MD) were re-classified as AML with myelodysplasia related changes (AML MRC). The remaining 30 AUL patients presented with similar age, blood counts, bone marrow cellularity, and blast percentage as the 37 AML MD patients (all p 〉 0.05). Comparison of immunophenotype in the two groups showed that AUL blasts had more frequent expression of TdT (p=0.0003) and lacked myeloid markers (CD117, CD13 or CD33 p0.05) were seen between these two groups. The frequency of abnormal karyotype was similar between AUL and AML MD (16/30 [53%] vs 15/37 [41%], respectively). The most common mutations identified in AUL were PHF6 (7/18), SRSF2 (7/18), RUNX1 (7/23), ASXL1 (6/23) and BCOR (5/16). Compared to AML MD, AUL cases were characterized by frequent mutations in PHF6 (7/18 vs 1/23, p=0.013) and SRSF2 (7/18 vs 2/22 p=0.028). Limiting AUL cases to only those with 1 myeloid marker or less also showed similar findings with more frequent mutations in PHF6 (7/16 vs 1/25, p=0.0031), SRSF2 (6/15 vs 3/26 p= 0.018) and trend towards higher BCOR frequency (5/15 vs 2/26, p=0.078) in AUL patients as compared to AML MD. RUNX1 mutation was seen in 7/23 AUL and 8/29 AML MD (p〉0.05). 19/30 AUL patients received induction chemotherapy (AML-type regimen in 18 cases and an ALL-type regimen in 1 case) and 15/30 achieved complete remission. In 10 AUL patients who relapsed, 9 showed identical immunophenotype and one case showed expression of CD13 and CD33. Outcome data in the subset of patients who received induction showed no difference in OS, RFS, or rates of complete remission between AUL and AML MD groups (p〉0.05). The 28 AML MRC cases that were originally classified as AUL or AML MD presented with lower WBC (p=0.026), more frequent abnormal karyotype (27/28) specifically complex karyotype (20/28 p=0.002), frequent TP53 mutations (p=0.0002) when compared to the AUL group. AML MRC patients showed worse overall OS (p=0.029) as compared with AUL patients and a trend toward worse outcome as compared with AML MD (p=0.068). Conclusions: In this largest series to date, AUL group shows distinct characteristics from AML MD, including more frequent PHF6 and SRSF2 mutations and expression of TdT. However, clinical outcome is similar between the two groups in patients treated with induction chemotherapy. Cases reclassified as AML-MRC had shorter survival compared to de novo AUL and trend towards worse outcome when compared to AML MD patients. These results suggest a genetic rationale for the separation of AUL as a distinct entity from AML MD and also support the WHO classification of cases with history of prior MDS and/or MDS-type karyotype findings as AML-MRC. Disclosures Garcia: Celgene: Consultancy.

Description: Introduction: Myelodysplastic syndromes (MDS) are neoplasms characterized by cytopenias, high risk of leukemic progression, and poor overall survival. Chemotherapy for MDS is not curative, and no new drugs have been approved for the treatment of MDS in over a decade. Clinical trials should be considered at any time during the management of patients with MDS, but enrollment criteria may be barriers that limit accrual. In this study, we extracted MDS clinical trial data from clinicaltrials.gov, and compared study indications and characteristics, including inclusion and exclusion criteria. Methods: We identified MDS clinical trials via clinicaltrials.gov (accessed: April 16, 2018). Studies were included if they allowed "MDS," "Myelodysplastic syndromes," "Preleukemia," and/or "Myelodysplasia," based on the pre-defined 'related terms' criteria in the database. We included interventional studies open in the United States that were listed as recruiting or not yet recruiting, for adults (age 18-64) and older adults (age 65+). We excluded studies that were observational in nature, involved a transplant-based intervention, or did not use a pharmacological intervention. We coded inclusion and exclusion criteria based on those provided by study authors in the database. Results: 83 interventional clinical trials enrolling patients with MDS were identified. Studies started enrollment between 4/1/2013 and 3/27/2018, and anticipated reaching the primary objective between 5/1/2017 and 6/1/2025. The median planned study duration was 38 mo (range 10-95). In total, studies sought to enroll 8866 patients over 273 study-years; the median study enrollment estimate was 1.7 patients/month, or across all trials 247 patients/month. Clinical trials could be exclusive to MDS patients (n=28), include MDS patients and other myeloid malignancies e.g. AML (n=44), or include MDS patients and other cancers including solid tumors (n=11). For clinical trials exclusive to MDS, the total enrollment goal was 1966 patients over 96 study-years, with a median rate of 1.4 patients/month (range 0.3-13.2) or total of 63 patients/month across all studies. 33 trials were phase 1 studies, 17 were phase 1/2, 26 were phase II, 1 trial was phase 2/3, and 6 were phase III studies. The primary endpoint was typically MTD (n=50) or ORR (n=22), while 5 studies had an OS endpoint. Most trials specified "higher risk" MDS (n=44); 8 specified "lower risk" MDS and 31 allowed all MDS risk or did not specify risk (Figure 1). Lower risk MDS studies were all exclusive to MDS patients. Inclusion criteria related to MDS risk varied significantly according to whether a study was MDS-specific or not (p=0.021): 82% of MDS-specific trials had risk exclusions, compared to 72% of myeloid trials, and only 36% of trials open across cancers. Of 52 trials specifying MDS risk, 20 included IPSS criteria, 24 included IPSS-R criteria, and 27 had blast count criteria. Lower risk MDS criteria was variably defined as IPSS low or INT-1 disease (n=3), IPSS-R very low or low risk (n=1), IPSS-R VL, L, or intermediate risk (n=4), or blast counts 〈 5% (n=1), 〈 10% (n=2), or 5% (n=12) or 〉10% blasts (n=12). Most studies specified exclusion of CNS disease, even though CNS involvement is exceptionally rare in MDS. 43 trials excluded concurrent cardiovascular disease; most often (n=18) requiring 6mo since a cardiovascular event. 46 trials had language excluding concurrent cancers, including 4 that did not allow any prior cancer, and 17 required ³24mo disease free. Exclusions for prior cancers did not vary according to primary outcome (MTD or PK, vs ORR/OS, p=0.16). 20 of 56 studies with MTD or early outcomes (e.g. PK) required cancer-free intervals of ³1y, while 7 allowed concurrent cancers if not on active therapy. Discussion: Currently enrolling MDS clinical trials show significant variation in their inclusion and exclusion criteria. Heterogeneous definitions of basic entry criteria, such as the definition of higher- and lower-risk MDS, may cause barriers to enrollment. Disclosures Brunner: Takeda: Research Funding; Novartis: Research Funding; Celgene: Consultancy, Research Funding. Garcia:Celgene: Consultancy.

Description: Background: Patients (pts) with MDS or AML who relapse after allogeneic transplantation (allo-HCT) have a very poor prognosis. Hypomethylating agents (HMA) and checkpoint blockade with the anti-CTLA4 blocking antibody ipilimumab (IPI) have each induced responses with acceptable toxicity in AML pts who relapse after allo-HCT. We hypothesized that adding decitabine (DAC) would improve response compared with IPI alone by activating and promoting T cell-mediated anti-leukemic immune reactivity. We are conducting a multicenter phase I study (CTEP 10026) of DAC plus IPI in pts with R/R MDS/AML in both post allo-HCT and transplant-naïve settings to assess safety and estimate efficacy. Methods: The primary objective is to determine the maximum tolerated dose (MTD) or RP2D of combination DAC + IPI in pts with R/R MDS/AML who are post allo-HCT (Arm A) or transplant-naïve (Arm B). Cohorts of 3-6 are sequentially enrolled in 3 dose levels (DL) of IPI using a 3+3 design with expansion in each arm; DLs 0-2 are 3, 5 and 10 mg/kg, respectively. Eligibility for both arms: relapsed AML (extramedullary or ≥ 5% blasts) or R/R MDS (≥ 5% blasts) or unfit elderly AML; Arm A only: ≥ 2 wks off systemic immunosuppressive (IS) therapy, T cell chimerism ≥ 20%, and no prior acute GVHD ≥ gr III. DLT is defined as ≥ gr 3 non-heme, ≥ gr 3 acute GVHD or ≥ gr 3 steroid-refractory immune-related adverse events (AEs) occurring within 8 weeks from first IPI dose. Epigenetic priming with DAC lead-in cycle 0 was followed by combination cycles of DAC + IPI. DAC is given at 20 mg/m2 days 1-5 q 28 days. IPI is given on day 1 of cycles 1-4 and every other cycle in cycles 5-12. Pts who discontinued study either in cycle 0 or DLT period without IPI-toxicity were replaced. Arm A opened after safety was confirmed at DL0 in Arm B. Results: As of June 9, 2019, 26 pts (15M, 11 F) have enrolled in this on-going trial. Of the 12 pts (11 AML and 1 MDS) enrolled in Arm A (post allo-HCT), median age was 66.5 (range 29-74) and 9 had previously received HMA. 7 of 8 pts in DL0 (1 progressed in cycle 0) and 3 of 4 pts in DL1 (1 died from pneumonia in cycle 0) received DAC + IPI. DL0 was expanded to 6 to confirm safety without DLT. Median treatment duration after first IPI dose was 5 cycles (range 1-7); 4 pts continue on trial. Common AEs were gr 1-2 dyspnea (n=4), gr 1-3 fatigue (n=4), and gr 1-2 fever (n=4). Gr 3 AEs were febrile neutropenia (n=2), pneumonia (n=1), and candidemia (n=1). Gr 1 immune-related dermatitis (n=1) reversed with steroids. Acute GVHD was not observed. Moderate-severe chronic GVHD was noted in 2 pts mainly involving skin, which was responsive to photopheresis and oral IS. Though 1 CR and 1 marrow CR have been observed at DL0, dose-escalation up to DL2 is on-going to determine MTD. Of the 14 pts (11 AML and 3 MDS) enrolled in Arm B (transplant naïve), median age was 75.5 (range 34-82) and 9 had previously received HMA. 4 of 6 pts in DL0 (1 progressed and 1 withdrew in cycle 0), 3 of 5 pts in DL1 (2 withdrew in cycle 0) and 3 of 3 pts in DL2 received DAC + IPI. Median treatment duration after first IPI dose was 4 cycles (range 1-8); 3 pts remain on study. Common AEs were gr 1-3 fatigue (n=9), gr 1-2 anorexia (n=5), and gr 3 febrile neutropenia (n=8). Immune-related gr 2 colitis (n=1) and gr 2/3 (n=4) dermatitis were all steroid-responsive. Of the 10 pts who received at least one IPI dose, 5 (50%) achieved an objective response including 3 CR, 1 CRi and 1 PR. All responses were observed in AML pts, including 1 with only skin involved. Expansion to confirm MTD is underway. No treatment-related deaths or DLTs were observed in either Arm. Reasons for discontinuation after IPI: progression (n=9), proceeding to allo-HCT or DLI (n=2), withdrawal (n=1), stroke due to underlying atrial fibrillation (n=1) and disseminated nocardiosis (n=1). In both Arms, multiplex immunofluorescence (MIF) staining of BM biopsies revealed a higher density of CD3+CD4+ cells after 4 cycles of DAC + IPI in 4 responders (R) compared to 4 non-responders (NR) (p=0.0433). Longitudinal MIF IHC in an Arm B responder identified the increasing presence of a tumor immune infiltrate composed of CD3+CD8+GZMB+ T cells prior to achieving CR (Fig 1). Conclusions: Combination DAC + IPI is tolerable and has encouraging clinical activity in post allo-HCT and transplant naïve pts with R/R MDS/AML. Ongoing studies focus on comparing the immunologic and genetic characteristics of the tumor immune infiltrate in each cohort to understand the contribution of alloimmunity to treatment response. Disclosures Garcia: Abbvie: Research Funding; Genentech: Research Funding. Keng:agios: Membership on an entity's Board of Directors or advisory committees. Brunner:Jazz Pharma: Membership on an entity's Board of Directors or advisory committees; Forty Seven Inc: Membership on an entity's Board of Directors or advisory committees; Novartis: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Astra Zeneca: Research Funding. Khaled:Omeros: Consultancy; Alexion: Consultancy, Speakers Bureau; Daiichi Sankyo: Other: Travel support. Steensma:H3 Biosciences: Other: Research funding to institution, not investigator.; Arrowhead: Equity Ownership; Onconova: Consultancy; Stemline: Consultancy; Aprea: Research Funding; Pfizer: Consultancy; Summer Road: Consultancy; Astex: Consultancy. Winer:Jazz Pharmaceuticals, Pfizer: Consultancy. Cutler:Omeros: Consultancy; Kadmon: Consultancy; BiolineRx: Other: DSMB; Cellect: Other: DSMB; Kalytera: Other: DSMB; ElsaLys: Consultancy; Genentech: Consultancy; Pharmacyclics: Consultancy; Fate Therapeutics: Consultancy; Incyte: Consultancy; Jazz: Consultancy; BMS: Consultancy. Ho:Omeros Corporation: Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Research Funding; Jazz Pharmaceuticals: Consultancy. Neuberg:Madrigal Pharmaceuticals: Equity Ownership; Pharmacyclics: Research Funding; Celgene: Research Funding. Lindsley:Takeda Pharmaceuticals: Consultancy; Jazz Pharmaceuticals: Research Funding; Medlmmune: Research Funding. Galinsky:ABIM: Other: Member of specialty oncology board; Merus Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; AbbVie Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Pfizer Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees. Ritz:TScan Therapeutics: Consultancy; LifeVault Bio: Consultancy; Kite Pharma: Research Funding; Talaris Therapeutics: Consultancy; Draper Labs: Consultancy; Avrobio: Consultancy; Celgene: Consultancy; Merck: Research Funding; Equillium: Research Funding; Aleta Biotherapeutics: Consultancy. Davids:AbbVie, Acerta Pharma, Adaptive, Biotechnologies, Astra-Zeneca, Genentech, Gilead Sciences, Janssen, Pharmacyclics, TG therapeutics: Membership on an entity's Board of Directors or advisory committees; AbbVie, Astra-Zeneca, Genentech, Janssen, MEI, Pharmacyclics, Syros Pharmaceuticals, Verastem: Consultancy; Acerta Pharma, Ascentage Pharma, Genentech, MEI pharma, Pharmacyclics, Surface Oncology, TG Therapeutics, Verastem: Research Funding; Research to Practice: Honoraria. Wu:Pharmacyclics: Research Funding; Neon Therapeutics: Other: Member, Advisory Board. Stone:AbbVie, Actinium, Agios, Argenx, Arog, Astellas, AstraZeneca, Biolinerx, Celgene, Cornerstone Biopharma, Fujifilm, Jazz Pharmaceuticals, Amgen, Ono, Orsenix, Otsuka, Merck, Novartis, Pfizer, Sumitomo, Trovagene: Consultancy; Argenx, Celgene, Takeda Oncology: Other: Data and Safety Monitoring Board/Committee: ; Novartis, Agios, Arog: Research Funding. DeAngelo:Blueprint: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Abbvie: Research Funding; Glycomimetics: Research Funding; Amgen, Autolus, Celgene, Forty-seven, Incyte, Jazzs, Pfizer, Shire, Takeda: Consultancy. Soiffer:Jazz: Consultancy; Gilead, Mana therapeutic, Cugene, Jazz: Consultancy; Juno, kiadis: Membership on an entity's Board of Directors or advisory committees, Other: DSMB; Kiadis: Other: supervisory board; Mana therapeutic: Consultancy; Cugene: Consultancy. OffLabel Disclosure: Combination of ipilimumab and decitabine for MDS/AML treatment for patients who are post-transplant or transplant naive

Description: Introduction: Elderly pts with R/R AML not eligible for cytotoxic therapy have limited therapeutic options, and dismal outcomes with available therapies. In preclinical studies, inhibition of BCL-2 and MDM2 with Ven and Idasa, respectively, has demonstrated potent synergistic apoptotic activity. In this ongoing, open-label, Phase Ib study, the safety, tolerability, and preliminary efficacy of Ven+cobimetinib (Arm A) and Ven+Idasa (Arm B) is being assessed in R/R AML (NCT02670044). Initial analysis indicated a tolerable safety profile for Ven+Idasa. Here, we present updated safety and efficacy results from Arm B. Methods: Pts (≥60 years) with R/R AML or secondary AML, previously treated for an antecedent hematologic disease but treatment naïve for AML, and ineligible for cytotoxic therapy/allogeneic stem cell transplant were enrolled. The maximum tolerated dose of Ven+Idasa was determined by two-dimensional dose escalation. Pts received Ven orally (PO) daily (400 or 600mg) + Idasa PO daily on Days (D) 1-5 (150mg, 200mg, or 400mg) in 28-day cycles. Responses were assessed according to revised International Working Group Response Criteria 2003. Pharmacokinetic (PK) analyses were performed on plasma samples on Cycles (C) 1 and 2, D1 and 5, and C4, D1. Exploratory assessments included minimal residual disease (MRD), assayed centrally at Covance Laboratories using 8-color flow cytometry. Data cut-off was June 21, 2019. Results: At data cut-off, 49 pts were treated with Ven+Idasa. Median age was 72 years (range 62-93); Eastern Cooperative Oncology Group performance status 0-1: 84%; refractory AML: 57%; relapsed AML: 33%; and secondary previously untreated AML: 10%; Intermediate-I or Intermediate-II European Leukemia Net (ELN) risk classification: 66%; adverse ELN classification: 30%; de novo (49%) versus secondary (51%) AML; and median prior lines of treatment: 1 (range 1-4). Most common adverse events (AEs; any grade) irrespective of attribution were diarrhea (90%) and nausea (78%); the most common grade ≥3 AEs were febrile neutropenia (45%), neutropenia (27%), and thrombocytopenia (25%; Table 1). Laboratory tumor lysis syndrome occurred in 3 pts; none resulted in treatment discontinuation. Ven and Idasa treatment discontinuation due to AEs were noted in 18% and 20%, respectively, most commonly due to infections. 30- and 60-day mortality rates were 6% and 17%, respectively. No apparent PK drug-drug interaction was found between Ven and Idasa; overlap in Ven and Idasa exposure was substantial over the doses tested. Anti-leukemic response rate (complete response [CR] + CR with incomplete platelet count recovery [CRp] + CR with incomplete blood count recovery [CRi] + partial response [PR] + morphologic leukemia-free state [MLFS]) across all dose levels was 41% (Table 2). Across the two Ven 600mg cohorts being considered for the recommended Phase II dose (RP2D), the anti-leukemic response rate was 50% (CR+CRp+CRi rate 29%). Median time to CR+CRp+CRi+PR was 1.4 months (range 1-3), with a median response (CR+CRp+CRi) duration of 4.9 months (range 0.6-9.7). Median overall survival in all pts and in the Ven 600mg cohorts was 4.4 months and 5.7 months, respectively, with a median follow-up of 3.4 months (range 0.03-18). Individual pt responses are shown in Figure 1. MRD negativity (

Description: Background: Early prediction of response to novel chemotherapy combinations for patients diagnosed with relapsed or refractory acute myeloid leukemia (R/R AML) may have clinical utility. We conducted a phase 1 clinical trial (NCT01904643) of lenalidomide (LEN) given prior to MEC (Mitoxantrone + Etoposide + Cytarabine) salvage chemotherapy (LEN+MEC) for patients with R/R AML. Although the clinical trial was terminated due to administrative reasons, we explored the utility of FACS-based BH3 and dynamic BH3 profiling (DBP) assays to predict for response. Standard BH3 profiling is a functional assay that uses synthetic peptides derived from the BH3 domains of pro-apoptotic BCL-2 family members to measure mitochondrial "priming" (a cell's readiness for apoptosis) (Ni Chonghaile, Science, 2011). DBP measures whether short term incubation with drug enhances priming (Montero J, Cell, 2015). Methods: Primary objective was to assess the safety/toxicity profile (DLTs and MTD) of LEN+MEC. LEN was administered 5-7 days prior to MEC and dose was escalated using an mTPI design with a target toxicity level of 30%. Dose levels (DL) included LEN given at doses of 15mgx5d (DL1), 15mgx7d (DL2), 25 mgx5d (DL3), 25mgx7d (DL4), 50mgx5d (DL5), and 50 mgx7d (DL6). Dose-escalation decisions were made based on DLTs that occurred during induction chemotherapy. DLT was defined as persistent cytopenias in absence of disease, gr 3 or higher non-hematologic toxicity not due to underlying disease or intolerable gr 2 toxicities attributable to LEN. Blood/bone marrow samples were collected at pre-treatment, post LEN only, and post LEN+MEC therapy. Clinical response was defined per ELN guidelines. For correlative studies, standard BH3 and DBP assays were used to measure overall mitochondrial priming and individual anti-apoptotic protein dependencies. DBP was performed after overnight (~16h) treatment with LEN at various concentrations on pretreatment leukemic blasts. Delta priming, utilized as a readout, represents the change in mitochondrial outer membrane depolarization after LEN treatment as measured by cytochrome C release following exposure to BH3 peptides. Data analysis was performed blinded to clinical response. Receiver operating characteristic (ROC) curve analysis was used to determine the optimal cut-off level for respective clinical end points. Results: 17 total patients with R/R AML received LEN+MEC. Median age was 55 years (range: 22-72) with 12% Fav, 47% Int and 41% Adv risk by ELN risk stratification. 60% were heavily pre-treated. DLTs were observed in DL2 (n=1, gr 4 sepsis due to bacteremia), DL3 (n=1, gr 5 septic shock), and DL5 (n=1, gr3 bacteremia). MTD was not yet reached due to early study termination (although patients were treated at all 6 dose levels). No GVHD was observed among post-transplant patients. Composite remission rate among the 17 patients (CR + PR) was 35% (5 CR and 1 PR). Of the 5 patients who achieved CR, 3 of them eventually progressed. Median PFS and OS for the entire cohort was 2.30 (90% CI 1.84-3.47) and 4.60 (90% CI 2.84-22.10) months, respectively. To assess whether mitochondrial priming might correlate with clinical response, we first performed standard BH3 profiling with a series of peptides on 16 pretreatment bone marrow samples. Mitochondrial cytochrome c release in response to BIM-BH3 correlated weakly with clinical response. DBP on pretreatment myeloblasts in response to BIM (activator) or PUMA (sensitizer) peptides were able to stratify responders based on an increase in mitochondrial priming caused by ex vivo LEN treatment (P

Description: Abstract 2709 Introduction: RUNX1 is a critical transcription factor in the regulation of normal hematopoiesis. Inherited RUNX1 mutations have been identified as the culprit genetic lesion in Familial Platelet Disorder (FPD; OMIM 601399), a rare autosomal dominant condition with a propensity to myeloid malignancy. The spectrum of RUNX1 mutations causing the FPD/acute myeloid leukemia (AML) syndrome includes frameshift and termination mutations detected throughout the gene, and missense mutations clustered within the highly conserved RUNT homology domain (RHD), which is responsible for both DNA binding and heterodimerization with CBFβ/PEBP2β, the non-DNA binding regulatory subunit. We present a new FPD/AML pedigree with a novel missense mutation leading to a single amino acid change, L56S. This L56S mutation is the first reported point mutation in this syndrome to be found outside of the RHD. Patients and Methods: Our new pedigree involves a 41-year-old man (proband) diagnosed with myelodysplastic syndrome (MDS, specifically refractory anemia with excess blasts type-2) with a normal karyotype. He was initiated on azacitidine, which was administered on a seven-day treatment schedule every four weeks. Bone marrow biopsy analysis after six monthly cycles of azacitidine showed persistent MDS, with similar findings after a total of ten monthly cycles. Given his lack of a clinical response, his young age and good performance status, he was referred to The University of Chicago for allogeneic hematopoietic stem cell transplantation (HCT). Routine pre-transplant evaluation revealed mild thrombocytopenia (platelets = 123,000 K/μl) in his HLA-matched brother. In addition, his father was reported to have thrombocytopenia. Clinical concern for an inherited condition initiated the investigation for a RUNX1 mutation in the family. Results: We sequenced full-length cDNA synthesized from leukocyte-derived RNA collected from the proband's sibling with thrombocytopenia, and detected a novel missense germline mutation in exon 4 at nucleotide position 371, causing a T to C mutation leading to a single amino acid change in the RUNX1 protein, L56S. This amino acid substitution is located N-terminal to the RHD (aa 76–209). RUNX1 sequencing of the proband with MDS demonstrated the same mutation. The RUNX1 RHD and the transactivation domain remain intact in this mutant. Initial transactivation assays using a luciferase reporter assay performed in triplicate demonstrated similar levels of activation as wild-type RUNX1. Corresponding Western blot analysis showed similar levels of protein expression of both wild-type RUNX1 and mutant RUNX1 transfected cell lines using an anti-RUNX1-antibody. Current studies include determination of the transactivation ability of mutant RUNX1 with its heterodimerization partner, CBFβ/PEBP2β, testing the DNA binding ability of this RUNX1 mutant by electrophoretic mobility shift assay, and analysis of the RUNX1 cDNA for an acquired biallelic mutation in leukocytes collected from the proband's bone marrow aspirate at the time of diagnosis of bone marrow malignancy. Conclusions: FPD/AML is likely an underreported condition. Clinical suspicion for this inherited syndrome may be raised by the presence of mild to moderate thrombocytopenia in healthy siblings, and should lead to prompt screening for germline RUNX1 mutations to confirm an inherited predisposition and to prevent siblings carrying RUNX1 mutations from being selected as HCT donors. In vitro studies of identified RUNX1 mutations may elucidate potential mechanisms involved in the pathogenesis of the FPD/AML syndrome. Disclosures: No relevant conflicts of interest to declare.