FLT3 and LSD1 Inhibitor Combinations Synergistically Repress Growth of FLT3-Mutant Acute Myeloid Leukemia Via Blockage of MYC Function

Internal Tandem Duplication mutations of Fms Related Receptor Tyrosine Kinase 3 (FLT3), known as FLT3-ITD mutations, are associated with poor prognosis in Acute Myeloid Leukemia (AML). The clinical efficacy of inhibiting FLT3 in AML is limited by the rapid development of drug resistance and relapse, underscoring a need for more potent and durable treatment strategies. The early persistence of leukemic blasts during FLT3 inhibition is a key driver of resistance. We find that in combination, inhibitors of Lysine Specific Demethylase 1 (LSD1) potentiate the activity of FLT3 inhibitors, driving synergistic cell death. This novel therapeutic approach has the potential to drive deeper therapeutic responses in FLT3-Mutant AML, delaying or preventing the development of resistance. LSD1 is a dynamic DNA-associated protein that functions as a chromatin modifier and transcription factor. LSD1 removes methylation on both lysine 4 of histone H3 (H3K4), associated with transcriptional activation, and lysine 9 (H3K9), associated with transcriptional repression. Additionally, LSD1 has been reported to function as a transcription factor independent of its catalytic demethylase function. LSD1 inhibition reduces cell proliferation in several cancer types. In AML specifically, inhibition of LSD1 has been reported to activate enhancers associated with genes that promote differentiation. We hypothesized that combining LSD1 inhibition with FLT3 inhibition in FLT3-ITD AML would result in synergistic effects on cell viability through reactivating differentiation pathways and more strongly blocking proliferation. In this study, we aimed to examine the efficacy, transcriptional effects, and changes in chromatin dynamics when combining LSD1 inhibition with FLT3 inhibition in a FLT3-ITD mutant cell line and patient samples. We used matrix combination screening to determine that combining the FLT3 inhibitor Quizartinib with LSD1 inhibitors (GSK-2879552 or ORY-1001) synergistically represses cell viability in the FLT3-ITD mutant MOLM-13 cell line and in multiple primary AML samples. RNA-seq followed by Gene Set Enrichment Analysis revealed that combining LSD1 and FLT3 inhibition synergistically represses target genes of the oncogenic transcription factor MYC. This finding was corroborated through high-throughput genome-wide profiling of histone marks, using the recently developed technique Cleavage Under Targets and Tagmentation (CUT&Tag). Specifically, we discovered several promoter regions in which acetylation of lysine 27 of Histone H3 (H3K27Ac), associated with transcriptional activation, was repressed by combining LSD1 and FLT3 inhibition. The genes associated with these regions were strongly enriched for known MYC target genes. Through additional genomic profiling methods including ChIP-seq and ATAC-seq, we have established potential roles for several DNA-binding transcription factors including CEBPA, RUNX1, STAT5, and LSD1 itself, that may mediate repression of MYC function resulting from combining LSD1 and FLT3 inhibition. Together, our work establishes LSD1 and FLT3 inhibitor combinations as a promising treatment strategy in FLT3-ITD AML. Importantly, this study identifies combined FLT3 and LSD1 inhibition as an effective strategy to indirectly target MYC function, as MYC is often referred to as an "undruggable" target. Furthermore, it has the potential to drive deeper molecular responses in FLT3-mutant AML, decreasing the likelihood of treatment resistance. Disclosures Druker: Bristol-Myers Squibb: Research Funding; Blueprint Medicines: Consultancy, Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; ARIAD: Research Funding; Cepheid: Consultancy, Membership on an entity's Board of Directors or advisory committees; Third Coast Therapeutics: Membership on an entity's Board of Directors or advisory committees; VB Therapeutics: Membership on an entity's Board of Directors or advisory committees; Millipore (formerly Upstate Biotechnology): Patents & Royalties; Pfizer: Research Funding; The RUNX1 Research Program: Membership on an entity's Board of Directors or advisory committees; Gilead Sciences: Consultancy, Membership on an entity's Board of Directors or advisory committees; Vivid Biosciences: Membership on an entity's Board of Directors or advisory committees; Patient True Talks: Consultancy; Oregon Health & Science University: Patents & Royalties; Novartis Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding; MolecularMD (acquired by ICON): Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Henry Stewart Talks: Patents & Royalties; Iterion Therapeutics (formerly Beta Cat Pharmaceuticals): Membership on an entity's Board of Directors or advisory committees; Aptose Therapeutics Inc. (formerly Lorus): Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Merck & Co: Patents & Royalties; GRAIL: Consultancy, Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; Aileron Therapeutics: Membership on an entity's Board of Directors or advisory committees; McGraw Hill: Patents & Royalties; Leukemia & Lymphoma Society: Research Funding; ALLCRON: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Dana-Farber Cancer Institute: Patents & Royalties; EnLiven: Consultancy, Research Funding. Maxson:Gilead Sciences: Research Funding; Ionis Pharmaceuticals: Other: Joint oversight committee for a collaboration between OHSU and Ionis Pharmaceuticals.

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A Phase-Ib/II Clinical Evaluation of Ponatinib in Combination with Azacitidine in FLT3-ITD and CBL-Mutant Acute Myeloid Leukemia (PON-AZA study)

Blood ◽

10.1182/blood-2021-154247 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 2350-2350

Author(s):

David Kipp ◽

Sun Loo ◽

Andrew Charles Perkins ◽

Steven W Lane ◽

Emily Blyth ◽

...

Keyword(s):

Board Of Directors ◽

Research Funding ◽

Loss Of Function ◽

Publicly Traded ◽

Advisory Committees ◽

Best Response ◽

Flt3 Inhibitor ◽

Flt3 Inhibitors ◽

Eliza Hall Institute ◽

Hall Institute

Abstract Introduction Despite the advent of targeted therapy for FLT3-mutated AML, unmet need still exists for patients unfit for intensive chemotherapy, with no evidence that overall survival (OS) can be improved by combining either venetoclax (Konopleva et al., ASH 2020) or gilteritinib (Astellas press release, December 2020) with azacitidine. Although gilteritinib has been shown to improve median OS from 5.5 to 9.8 months, the majority will relapse (Perl et al., 2019). Adaptive on-target gilteritinib resistance may be due to the FLT3-F691L gatekeeper mutation, whereas off-target resistance may be due to loss-of-function variants in CBL, which encodes an E3 ubiquitin-protein ligase that negatively regulates FLT3 (McMahon et al, 2019). Ponatinib is a type-1 FLT3 inhibitor that is active in vitro against FLT3 F691L (Smith et al., 2013) and had an overall response rate (ORR) of 43% in a small pilot phase-I study (Talpaz et al., 2011). Combination of a FLT3 inhibitor with azacitidine may antagonize the synergistic hypermethylation reported for FLT3-ITD in association with epigenetic mutations (Shih et al., 2015). CBL loss-of-function mutations may also enhance responsiveness to FLT3 inhibitors (Taylor et al, 2015). We thus hypothesize that the combination of ponatinib and azacitidine could mitigate the rapid evolution of drug resistance typical of more selective FLT3 inhibitors used as single agents. Methods A phase-Ib study was conducted with the primary objective safety and key secondary objective preliminary efficacy of azacitidine in combination with ponatinib in patients with FLT3-ITD AML failing prior therapy or unfit for intensive chemotherapy. Exploratory objectives included mechanisms of ponatinib resistance and responsiveness of CBL-mutant AML to FLT3 inhibition. At dose level 1 (DL1), patients received azacitidine 60 mg/m 2 on days 1-5 and 8-9 and ponatinib 30 mg daily on days 5-25 of each cycle. In patients not achieving CR or CRi after cycle 1, the ponatinib dose was increased to 45 mg during cycle 2. For dose level 2 (DL2), the dose of azacitidine was increased to 75 mg/m 2. Results Thirty-one patients were evaluable for response. Median age was 67 years (range, 26-87). Frequency of prior lines of therapy was 0 (15%), 1 (46%), 2 (23%) or 3 (8%). Four patients had a history of prior allogeneic hematopoietic cell transplant and one had previously received a FLT3 inhibitor. FLT3-ITD was present in 28 patients (median VAF 0.33; range, 0.009-17.95) and 3 had inactivating CBL mutations. A total of 20 patients were treated at DL1 and 12 patients at DL2. There were two grade-4 DLTs (raised AST/ALT [DL1] and tubulointerstitial nephritis [DL2]). Three grade-2 thromboembolic events were observed (two cannula-related DVTs and a distal lower-limb DVT). There were two grade-5 AEs (infection and cardiac failure), which were not considered drug related. The most common grade-3-4 AEs were febrile neutropenia (57%), neutropenia (47%), infections (47%), thrombocytopenia (40%) and anaemia (27%). Cardiac arrhythmias (atrial fibrillation/flutter, bradycardia, sinus tachycardia and ventricular tachycardia [1 patient]) were observed in 30% of patients. Of these, 80% were grade 1 or 2 and only one was considered by the investigator to be related to study treatment. Response was evaluable in 23 of 31 patients. Nine patients (39%) achieved CR or CRi, 3 (13%) achieved a PR and 8 (35%) achieved SD (ORR 52%). ORR at DL1 and DL2 was 43% and 66%, respectively. Median time to best response was 1.4 months (range 1.0-11.9). Median duration of best response was 12.9 months at both dose levels. Median OS for DL1 was 6.5 months and not reached for DL2. Despite shorter follow-up, DL2 patients experienced better OS than DL1 patients (p = 0.015). Responses were seen in 2 of 4 patients with post-allograft relapse. Two of three patients with a CBL mutation responded (1 CR and 1 CRi). Eradication of the CBL mutation was seen in one patient, who remains on therapy after 15 cycles. Molecular studies to investigate dynamic changes in molecular architecture are ongoing. Conclusions The recommended phase-II dose of ponatinib is 30 mg on days 5-25 and that of azacitidine is 75 mg/m 2 for seven doses each cycle. The ORR was 52% and durable disease control was observed, especially in patients receiving DL2. Preliminary efficacy was observed in CBL-mutated patients. Further clinical investigation of this regimen is warranted in patients with FLT3- or CBL-mutant AML. Figure 1 Figure 1. Disclosures Kipp: Novartis: Honoraria. Perkins: Celgene: Consultancy; Novartis: Consultancy, Honoraria, Speakers Bureau; Abbvie: Honoraria, Speakers Bureau. Lane: Novartis: Consultancy; Geron: Consultancy; BMS: Consultancy, Research Funding; Abbvie: Honoraria; Astellas: Membership on an entity's Board of Directors or advisory committees. Enjeti: Sanofi: Honoraria; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AbbVie: Honoraria; Roche: Speakers Bureau; Astra Zeneca: Honoraria. Bajel: Abbvie, Amgen, Novartis, Pfizer: Honoraria; Amgen: Speakers Bureau. Reynolds: Novartis AG: Current equity holder in publicly-traded company; Abbvie: Research Funding; Alcon: Current equity holder in publicly-traded company. Wei: Abbvie, Amgen, Astellas, AstraZeneca, Celgene/BMS, Genentech, Janssen, MacroGenics, Novartis, Pfizer, and Servier: Membership on an entity's Board of Directors or advisory committees; Novartis, Abbvie, Celgene/BMS: Speakers Bureau; Former employee of Walter and Eliza Hall Institute: Patents & Royalties: Prof. Andrew Wei is a former employee of the Walter and Eliza Hall Institute and is eligible for a fraction of the royalty stream related to Venetoclax; Abbvie, Amgen, Astellas, AstraZeneca, Celgene/BMS, Genentech, Janssen, MacroGenics, Novartis, Pfizer, and Servier: Honoraria; Servier: Consultancy; Abbvie, Amgen, AstraZeneca, Celgene/BMS, Novartis, Servier and F. Hoffmann-La Roche: Research Funding. OffLabel Disclosure: Ponatinib - used as an experimental therapy for AML in combination with azacitidine

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Preliminary Results from a Phase 1 Study of APVO436, a Novel Anti-CD123 x Anti-CD3 Bispecific Molecule, in Relapsed/Refractory Acute Myeloid Leukemia and Myelodysplastic Syndrome

Blood ◽

10.1182/blood-2020-141619 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 11-12

Author(s):

Justin M. Watts ◽

Tara Lin ◽

Eunice S. Wang ◽

Alice S. Mims ◽

Elizabeth H. Cull ◽

...

Keyword(s):

Acute Myeloid Leukemia ◽

High Risk ◽

Board Of Directors ◽

Myeloid Leukemia ◽

Research Funding ◽

Phase 1 ◽

Cytokine Release ◽

Publicly Traded ◽

Advisory Committees ◽

Acute Myeloid

Introduction Immunotherapy offers the promise of a new paradigm for patients with relapsed/refractory (R/R) acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). CD123, the IL-3 receptor alpha-chain, represents an attractive target for antibody therapies because of its high expression on AML/MDS blasts and leukemic stem cells compared to normal hematopoietic stem and progenitor cells. APVO436, a novel bispecific anti-CD123 x anti-CD3 ADAPTIR™ molecule, depleted CD123+ cells in AML patient samples ex vivo (Godwin et al. ASH 2017), reduced leukemia engraftment in a systemic AML xenograft model (Comeau et al. AACR 2018), and transiently reduced peripheral CD123+ cells in non-human primates with minimal cytokine release and in a dose-dependent fashion (Comeau et al. AACR 2019). These data provide a basis for the clinical application of APVO436 as a treatment in AML and MDS. Here, we report preliminary data from a first-in-human dose-escalation study of APVO436 in patients with R/R AML and high-risk MDS. Study Design/Methods This ongoing Phase 1/1b study (ClinicalTrials.gov: NCT03647800) was initiated to determine the safety, immunogenicity, pharmacokinetics, pharmacodynamics, and clinical activity of APVO436 as a single agent. Major inclusion criteria were: R/R AML with no other standard treatment option available, R/R MDS with > 5% marrow blasts or any peripheral blasts and failure of a hypomethylating agent, ECOG performance status ≤ 2, life expectancy > 2 months, white blood cells ≤ 25,000 cells/mm3, creatinine ≤ 2 x upper limit of normal (ULN), INR and PTT < 1.5 x ULN and alanine aminotransferase < 3 x ULN. Patients were not restricted from treatment due to cytogenetic or mutational status. Intravenous doses of APVO436 were administered weekly for up to six 28-day cycles (24 doses) with the option to continue dosing for up to 36 total cycles (144 doses). Flat and step dosing regimens were escalated using a safety-driven modified 3 + 3 design. Pre-medication with diphenhydramine, acetaminophen, and dexamethasone was administered starting with dose 1 to mitigate infusion related reactions (IRR) and cytokine release syndrome (CRS). First doses and increasing step doses of APVO436 were infused over 20-24 hours followed by an observation period of 24 hours or more. Bone marrow biopsies were performed every other cycle with responses assessed by European Leukemia Net 2017 criteria for AML or International Working Group (IWG) 2006 criteria for MDS. Results The data cut-off for this interim analysis was July 9, 2020. Twenty-eight patients with primary R/R AML (n=19), therapy-related R/R AML (n=3), or high-risk MDS (n=6) have been enrolled and received a cumulative total of 186 doses. The number of doses received per patient ranged from 1 to 43 (mean of 6.4 doses). Most patients discontinued treatment due to progressive disease; however, blast reduction was achieved in 2 patients, with one patient with MDS maintaining a durable response for 11 cycles before progressing. APVO436 was tolerated across all dose regimens in all cohorts tested. The most common adverse events (AEs), regardless of causality, were edema (32%), diarrhea (29%), febrile neutropenia (29%), fever (25%), hypokalemia (25%), IRR (21%), CRS (18%), chills (18%), and fatigue (18%). AEs ≥ Grade 3 occurring in more than one patient were: febrile neutropenia (25%), anemia (18%), hyperglycemia (14%), decreased platelet count (11%), CRS (11%), IRR (7%), and hypertension (7%). After observing a single dose limiting toxicity (DLT) at a flat dose of 9 µg, step dosing was implemented and no DLTs have been observed thereafter. No treatment-related anti-drug antibodies (ADA) were observed. Transient serum cytokine elevations occurred after several reported IRR and CRS events, with IL-6 most consistently elevated. Conclusions Preliminary results indicate that APVO436 is tolerated in patients with R/R AML and MDS at the doses and schedules tested to date, with a manageable safety profile. Dose escalation continues and the results will be updated for this ongoing study. Disclosures Watts: BMS: Membership on an entity's Board of Directors or advisory committees; Aptevo Therapeutics: Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Rafael Pharma: Membership on an entity's Board of Directors or advisory committees; Jazz: Membership on an entity's Board of Directors or advisory committees; Genentech: Membership on an entity's Board of Directors or advisory committees. Lin:Ono Pharmaceutical: Research Funding; Pfizer: Research Funding; Abbvie: Research Funding; Bio-Path Holdings: Research Funding; Astellas Pharma: Research Funding; Aptevo: Research Funding; Celgene: Research Funding; Genetech-Roche: Research Funding; Celyad: Research Funding; Prescient Therapeutics: Research Funding; Seattle Genetics: Research Funding; Mateon Therapeutics: Research Funding; Jazz: Research Funding; Incyte: Research Funding; Gilead Sciences: Research Funding; Trovagene: Research Funding; Tolero Pharmaceuticals: Research Funding. Wang:Abbvie: Consultancy; Macrogenics: Consultancy; Astellas: Consultancy; Jazz Pharmaceuticals: Consultancy; Bristol Meyers Squibb (Celgene): Consultancy; PTC Therapeutics: Consultancy; Stemline: Speakers Bureau; Genentech: Consultancy; Pfizer: Speakers Bureau. Mims:Leukemia and Lymphoma Society: Other: Senior Medical Director for Beat AML Study; Syndax Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Kura Oncology: Membership on an entity's Board of Directors or advisory committees; Novartis: Speakers Bureau; Agios: Consultancy; Jazz Pharmaceuticals: Other: Data Safety Monitoring Board; Abbvie: Membership on an entity's Board of Directors or advisory committees. Cull:Aptevo Therapeutics: Research Funding. Patel:Agios: Consultancy; Celgene: Consultancy, Speakers Bureau; DAVA Pharmaceuticals: Honoraria; France Foundation: Honoraria. Shami:Aptevo Therapeutics: Research Funding. Walter:Aptevo Therapeutics: Research Funding. Cogle:Aptevo Therapeutics: Research Funding; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees. Chenault:Aptevo Therapeutics: Current Employment, Current equity holder in publicly-traded company. Macpherson:Aptevo Therapeutics: Current Employment, Current equity holder in publicly-traded company. Chunyk:Aptevo Therapeutics: Current Employment, Current equity holder in publicly-traded company. McMahan:Aptevo Therapeutics: Current Employment, Current equity holder in publicly-traded company. Gross:Aptevo Therapeutics: Current Employment, Current equity holder in publicly-traded company. Stromatt:Aptevo Therapeutics: Current equity holder in publicly-traded company.

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A Phase 1/1b Safety Study of Prgn-3006 Ultracar-T™ in Patients with Relapsed or Refractory CD33-Positive Acute Myeloid Leukemia and Higher Risk Myelodysplastic Syndrome

Blood ◽

10.1182/blood-2020-139417 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 17-17

Author(s):

David A. Sallman ◽

Hany Elmariah ◽

Kendra L. Sweet ◽

Chetasi Talati ◽

Asmita Mishra ◽

...

Keyword(s):

T Cells ◽

Gene Transfer ◽

Board Of Directors ◽

Dose Escalation ◽

Myeloid Leukemia ◽

Research Funding ◽

Publicly Traded ◽

Advisory Committees ◽

Car T Cells ◽

Car T

Background: Therapeutic options for relapse or refractory (r/r) acute myeloid leukemia (AML) and hypomethylating agent (HMA) failure higher risk myelodysplastic syndrome (MDS) pts are limited with median overall survival of < 6 months. Consequently, novel therapies are urgently needed. CD33 is highly expressed on most myeloid leukemia stem cells with lesser expression on normal hematopoietic stem cell populations and minimal non-hematopoietic expression making CD33 a leading target in chimeric antigen receptor therapy (CAR-T) development for myeloid malignancies. However, additional barriers of CAR-T development in myeloid malignancies include long manufacturing period, expansion of CAR-T cells and potential toxicity related to on-target, off-tumor toxicity. Scientific Rationale: Current CAR-T cells utilize viral vectors for gene transfer and subsequent lengthy ex vivo expansion at centralized manufacturing facilities, which is costly and leads to cell product that is exhausted and short lived in vivo. Time is of the essence for pts with rapidly progressing disease such as r/r AML and the prolonged interval between apheresis to product infusion with current CAR-T cell therapies can be a disadvantage. Although allogeneic "off-the-shelf" products allow for rapid administration, challenges remain with rapid rejection. Precigen has developed UltraCAR-T platform to overcome these limitations by utilizing an advanced non-viral gene delivery system and a rapid, decentralized manufacturing process. UltraCAR-T cells are manufactured overnight at medical center's cGMP facility using patient's autologous T cells and administered back to patient only one day after gene transfer with no need for ex vivo expansion. PRGN-3006 UltraCAR-T cells co-express CD33 CAR, membrane bound IL-15 (mbIL15) and a kill switch. Preclinical studies have demonstrated that the expression of the mbIL15 on UltraCAR-T cells leads to maintenance of preferred stem-like memory phenotype (TSCM). Superior efficacy of UltraCAR-T cells was demonstrated in an aggressive murine xenograft model of AML where a single administration of PRGN-3006, only one day after gene transfer, showed significantly higher expansion and persistence; effectively eliminated tumor burden; and significantly improved overall survival compared to traditional CD33 CAR-T cells lacking mbIL15 expression (Blood (2019) 134(S1): 2660). Study Design: The PRGN-3006 UltraCAR-T cells are currently being evaluated in a Phase 1/1b first-in-human dose escalation/dose expansion clinical trial (NCT03927261). The study population includes adult pts (≥ 18 years) with relapsed or refractory AML and HMA failure higher risk MDS or chronic myelomonocytic leukemia (CMML) with ≥ 5% blasts. Pts who have relapsed post allogeneic stem cell transplant are allowed if > 3 months out from transplant without evidence of active graft versus host disease and off immunosuppression for 6 weeks. Key inclusion criteria include an absolute lymphocyte count ≥ 0.2k/µL, KPS > 60%, absence of other active malignancy within 1 year of study entry, daily corticosteroid dose < 10mg of prednisone daily, adequate organ function and a backup allogeneic donor should bone marrow aplasia occur. Hydroxyurea is allowed for cytoreduction with cessation 3 days prior to apheresis/infusion but can be reinitiated post-infusion. To test the hypothesis that expression of mbIL15 on PRGN-3006 cells is sufficient to promote CAR-T cell expansion and persistence, study subjects will receive PRGN-3006 infusion either without prior lymphodepletion (Cohort 1) or following lymphodepleting chemotherapy (Cohort 2 with fludarabine 30mg/m2 and cyclophosphamide 500mg/m2 days -5 to -3). Up to 5 dose levels are planned in dose escalation. All subjects will be followed for adverse events, CAR-T-related toxicities, disease response and PRGN-3006 cell expansion and persistence in blood and bone marrow compartments. In addition, the mechanisms of safety and effectiveness of PRGN-3006 cells will be evaluated with correlative assays of specific immune response pathways. Currently, the study is in the dose escalation phase and has cleared the lower dose level while demonstrating successful manufacturing of UltraCAR-T cells. Additionally, multi-center expansion of the trial is in progress. Disclosures Sallman: Celgene, Jazz Pharma: Research Funding; Agios, Bristol Myers Squibb, Celyad Oncology, Incyte, Intellia Therapeutics, Kite Pharma, Novartis, Syndax: Consultancy. Sweet:Agios: Membership on an entity's Board of Directors or advisory committees; Astellas: Honoraria; Takeda: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; Stemline: Honoraria; Novartis: Membership on an entity's Board of Directors or advisory committees; Incyte: Research Funding. Talati:Astellas: Speakers Bureau; Jazz: Speakers Bureau; AbbVie: Honoraria; Pfizer: Honoraria; BMS: Honoraria. Lankford:Precigen, Inc.: Current Employment. Chan:Precigen, Inc.: Current Employment, Current equity holder in publicly-traded company. Shah:Precigen, Inc.: Current Employment; Intrexon Corporation: Current equity holder in publicly-traded company. Padron:BMS: Research Funding; Novartis: Honoraria; Kura: Research Funding; Incyte: Research Funding. Komrokji:Novartis: Honoraria; Agios: Honoraria, Speakers Bureau; Acceleron: Honoraria; AbbVie: Honoraria; JAZZ: Honoraria, Speakers Bureau; Incyte: Honoraria; Geron: Honoraria; BMS: Honoraria, Speakers Bureau. Lancet:Abbvie: Consultancy; Agios Pharmaceuticals: Consultancy, Honoraria; Astellas Pharma: Consultancy; Celgene: Consultancy, Research Funding; Daiichi Sankyo: Consultancy; ElevateBio Management: Consultancy; Jazz Pharmaceuticals: Consultancy; Pfizer: Consultancy. Sabzevari:Precigen, Inc.: Current Employment, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Compass Therapeutics: Current equity holder in publicly-traded company. Bejanyan:Kiadis Pharma: Membership on an entity's Board of Directors or advisory committees.

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LSD1 Inhibitor CPI-482 Shows Efficacy and Prolongs Survival in Mouse Models of AML and Post-MPN AML in the Context of Constitutive JAK-STAT Pathway Activation

Blood ◽

10.1182/blood-2020-140186 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 50-51

Author(s):

Raajit K. Rampal ◽

John P. McGrath ◽

Aishwarya Krishnan ◽

Bing Li ◽

Wenbin Xiao ◽

...

Keyword(s):

Bone Marrow ◽

Board Of Directors ◽

Cell Lines ◽

Research Funding ◽

Myelogenous Leukemia ◽

Publicly Traded ◽

Private Company ◽

Advisory Committees ◽

Pathway Activation ◽

Stat Pathway

Several novel mechanism-based therapeutic modalities are currently being clinically investigated for the treatment of patients with acute myelogenous leukemia (AML), including agents that exploit genomic vulnerabilities, attenuate leukemia stem cell populations and/or or synergize with anti-leukemic cytotoxic/epigenetic therapies. Lysine-specific demethylase 1 (LSD1) is an enzyme that functions in transcriptional repression by catalyzing the removal of histone H3 lysine 4 methylation, a histone modification associated with transcriptionally competent gene enhancers and transcriptional start sites. Small molecule mediated inhibition of LSD1 alters the chromatin state and the transcriptional output of LSD1 target genes. Transcriptional 'reprogramming' by LSD1 inhibitors either causes a direct impact on cell fate and/or renders malignant cells more susceptible to the treatment with other cancer therapeutic agents. LSD1 inhibitors have shown encouraging phenotypic effects in myelogenous leukemia (AML) models but the key molecular determinants governing LSD1 inhibitor sensitivity remain to be further investigated. Here, we explored the in vitro sensitivity of 350 cancer cell lines to our LSD1 inhibitor CPI-482 to identify potential hyper-responder cell contexts. Four AML cell lines showed high sensitivity with low nanomolar concentration GI50s, each of which contained either a JAK2V617F mutation or a genetic aberration that resulted in JAK-STAT pathway activation. Oral administration of LSD1 inhibitor CPI-482 on a once daily or a once weekly dosing schedule resulted in significant tumor growth inhibition in SET-2 and HEL 92.1.7 JAK2 mutant AML xenograft mouse models. Given the unmet need and poor prognosis in post-MPN secondary AML (sAML) we then explored CPI-482 in a tertiary transplant post-MPN AML retroviral transduction murine model (Jak2V617F retrovirus transduced intoTp53 null bone marrow). Jak2V617F/Tp53 null spleen cells were transplanted into lethally irradiated recipient mice along with wild-type donor support whole bone marrow cells. Mice were randomized to treatment with vehicle, Ruxolitinib (60mg/kg twice daily) or CPI-482 (60mg/kg weekly). Once-weekly treatment with CPI-482 significantly improved survival compared to vehicle (p<0.001) or ruxolitinib (p<0.043) (Figure 1A). Spleen weights were significantly reduced by CPI-482 compared to ruxolitinib (p<0.05;Figure 2B). The white blood cell count was unchanged in mice treated with CPI-482 but increased in both vehicle and ruxolitinib treated mice. Evaluation at the time of terminal take-down of mice demonstrated a significant increase in the proportion of lineage positive cells in both the bone marrow and spleen (compared to vehicle, p<0.05) consistent with restoration of normal hematopoiesis (Figure 1D). Histopathologic evaluation of the spleen demonstrated marked reduction in infiltration by blast cells, restoration of lymphoid follicles, emergence of megakaryocytes (Figure 1E), and modest reductions in reticulin fibrosis in CPI-482 treated mice, which was not observed in ruxolitinib treated mice. Mice tolerated treatment with CPI-482 well, with no changes in weights of treated mice (Figure 1F). Treatment of the JAK2V617F mutant AML cell lines SET-2 and HEL with CPI-482 resulted in specific transcriptional effects, including increased expression of the myeloid differentiation markers LY96 and CD86 and inflammatory response genes. CPI-482 also resulted in upregulation of genes that are repressed by the HOXA9 oncogene in other leukemia contexts. The induction of specific CPI-482 mediated gene expression and phenotypic changes was recapitulated by knockdown of the transcription factor GFI1B, suggesting that, consistent with prior findings in other leukemia contexts, LSD1 functionally cooperates with GFI1B in JAK2V617F mutant AML cells. These data provide support for a potential therapeutic impact of the LSD1 inhibitor CPI-482 in AML and sAML in the context of the JAK2V617F mutation, and thus extend the previous findings that LSD1 inhibitors may have utility in JAK2V617F mutated malignant proliferative neoplasms. Given the pressing need for new therapies for sAML which evolves from a pre-existing MPN, we believe these data form the rationale for a mechanism based clinical trial in this adverse risk myeloid malignancy. Figure Disclosures Rampal: Pharmaessentia: Consultancy; Galecto: Consultancy; Abbvie: Consultancy; Stemline: Consultancy, Research Funding; Constellation: Research Funding; Incyte: Consultancy, Research Funding; Celgene: Consultancy; Promedior: Consultancy; CTI Biopharma: Consultancy; Jazz Pharmaceuticals: Consultancy; Blueprint: Consultancy. McGrath:Constellation Pharmaceuticals: Current Employment, Current equity holder in publicly-traded company. Xiao:Stemline Therapeutics: Research Funding. Nikom:Constellation Pharmaceuticals: Current Employment, Current equity holder in publicly-traded company. Wang:Constellation Pharmaceuticals: Current Employment, Current equity holder in publicly-traded company. Levine:Imago: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; C4 Therapeutics: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; Isoplexis: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria, Research Funding; Lilly: Consultancy, Honoraria; Janssen: Consultancy; Astellas: Consultancy; Morphosys: Consultancy; Novartis: Consultancy; Amgen: Honoraria; Gilead: Honoraria; Prelude Therapeutics: Research Funding; Qiagen: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Loxo: Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees. Trojer:Constellation Pharmaceuticals: Current Employment, Current equity holder in publicly-traded company.

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A Phase 3, Randomized, Double-Blind, Placebo-Controlled Study to Assess the Efficacy and Safety of Entospletinib in Combination with Intensive Induction and Consolidation Chemotherapy in Adults with Newly Diagnosed N ucleophosmin 1-mutated Acute Myeloid Leukemia

Blood ◽

10.1182/blood-2021-145773 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 1282-1282

Author(s):

John C. Byrd ◽

Jorge E. Cortes ◽

Mark D. Minden ◽

Thomas Oellerich ◽

Eytan M. Stein ◽

...

Keyword(s):

Acute Myeloid Leukemia ◽

Board Of Directors ◽

Myeloid Leukemia ◽

Research Funding ◽

Newly Diagnosed ◽

Publicly Traded ◽

Advisory Committees ◽

Double Blind ◽

Double Blind Placebo ◽

Acute Myeloid

Abstract Background: Spleen tyrosine kinase (SYK) is a component of both lymphoid and myeloid cell signaling pathways and has been implicated in the pathogenesis of a subset of acute myeloid leukemia (AML) defined by dysregulated expression of the HOXA9 and MEIS1 transcription factors. Entospletinib (ENTO) is an oral, selective SYK inhibitor that is acceptably tolerated when administered with intensive induction and consolidation in newly diagnosed AML patients. In a phase 2 study, following induction with cytarabine and daunorubicin (7+3) plus ENTO, higher rates of complete response (CR) or CR with incomplete hematologic recovery (CRi) were observed in patients with rearrangements of the KMT2A (MLL) gene (MLL-r) and mutations of the nucleophosmin 1 (NPM1) gene, both of which are associated with aberrant expression of HOXA9 and MEIS1, as compared to patients without these mutations. In an exploratory analysis, patients with HOXA9/MEIS1 expression levels above the median experienced superior overall survival (OS) as compared to patients with expression levels below the median. In the AGILITY trial, we hypothesize that the addition of ENTO to intensive induction/consolidation in newly diagnosed patients with NPM1-mutated AML will improve the rate of CR without evidence of measurable residual disease (MRD-negative CR) post-induction and duration of event-free survival (EFS). Methods: AGILITY will be a global, multi-center, double-blind, placebo-controlled trial of ENTO in combination with cytarabine plus daunorubicin or idarubicin induction (7+3) and age-adjusted high-dose cytarabine (HiDAC) consolidation in newly diagnosed AML patients aged 18-75 years who are candidates for intensive induction and harbor a documented NPM1 mutation based on local or central mutation testing. Patients with co-mutated FLT3 (internal tandem duplication or tyrosine kinase domain) and for whom midostaurin with 7+3 is indicated are excluded. Patients will be stratified based on age (<60 vs ≥60 years) and anthracycline administered during induction (daunorubicin vs idarubicin). Approximately 180 patients will be randomized to receive 7+3 induction and HiDAC consolidation with ENTO (400 mg orally twice daily) versus 7+3 induction and HiDAC with placebo. Patients with <5% leukemic blasts after 1 cycle of induction will proceed to the first cycle of HiDAC consolidation while patients with ≥5% residual blasts will undergo a second induction cycle. Patients who do not achieve CR after 2 cycles of chemotherapy (either 2 induction cycles or 1 induction and 1 consolidation cycle) plus ENTO or placebo will be designated as induction treatment failures (ITF). Patients who achieve or remain in CR after 2 chemotherapy cycles will be evaluated for MRD in bone marrow based on enumeration of mutant NPM1 alleles using a molecular assay. Patients may receive up to 3 cycles of consolidation with HiDAC and ENTO or placebo beyond chemotherapy cycle 2 per their original randomized treatment assignment. The number of consolidation cycles and timing of hematopoietic stem cell transplant (HSCT) or other post-consolidation therapy (if any) is at the discretion of the investigator. All patients will be followed for relapse and survival. The primary endpoint will be the rate of MRD-negative CR (<0.01% mutant NPM1 alleles). Patients without an evaluation of response and MRD after chemotherapy cycle 2 will be imputed as treatment failures for the analysis. A key secondary endpoint will be EFS, defined as time from randomization to the earliest occurrence of ITF, relapse from CR, or death from any cause. Patients without an event at the time of the EFS analysis will be censored at the last study evaluation they were event-free. EFS will be estimated using the Kaplan-Meier method and summarized by treatment group. Differences between treatment groups will be assessed with the log-rank test stratified by age (<60 vs ≥60 years) and choice of anthracycline in induction (daunorubicin vs idarubicin). OS will be analyzed in a similar manner. Key exploratory endpoints will be the correlation between recurring genomic mutations and response or progression and longitudinal assessment of peripheral blood for detection of NPM1-m alleles among patients who achieve MRD-negative CR post-induction. An independent data-monitoring committee will monitor emerging safety and efficacy data from this trial on an ongoing basis. Disclosures Byrd: Vincerx Pharmaceuticals: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Novartis, Trillium, Astellas, AstraZeneca, Pharmacyclics, Syndax: Consultancy, Honoraria; Newave: Membership on an entity's Board of Directors or advisory committees. Cortes: Bristol Myers Squibb, Daiichi Sankyo, Jazz Pharmaceuticals, Astellas, Novartis, Pfizer, Takeda, BioPath Holdings, Incyte: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Bio-Path Holdings, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Sun Pharma: Consultancy, Research Funding. Minden: Astellas: Consultancy. Oellerich: Roche: Consultancy; Gilead: Research Funding; Kronos Bio, Inc.: Consultancy; Merck KGaA: Consultancy, Research Funding. Stein: Syros Pharmaceuticals, Inc.: Consultancy; Daiichi Sankyo: Consultancy; PinotBio: Consultancy; Celgene: Consultancy; Bristol Myers Squibb: Consultancy; Jazz Pharmaceuticals: Consultancy; Foghorn Therapeutics: Consultancy; Blueprint Medicines: Consultancy; Gilead Sciences, Inc.: Consultancy; Abbvie: Consultancy; Janssen Pharmaceuticals: Consultancy; Genentech: Consultancy; Syndax Pharmaceuticals: Consultancy; Agios Pharmaceuticals, Inc: Consultancy; Novartis: Consultancy; Astellas: Consultancy. Elder: PharPoint Research, Inc.: Current Employment. Kumar: Kronos Bio, Inc.: Current Employment, Current equity holder in publicly-traded company. Bray: Kronos Bio, Inc.: Consultancy. DiMartino: Kronos Bio, Inc.: Current Employment, Current equity holder in publicly-traded company. Stock: Pfizer: Consultancy, Honoraria, Research Funding; amgen: Honoraria; agios: Honoraria; jazz: Honoraria; kura: Honoraria; kite: Honoraria; morphosys: Honoraria; servier: Honoraria; syndax: Consultancy, Honoraria; Pluristeem: Consultancy, Honoraria. OffLabel Disclosure: Entospletinib is an investigational therapy

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Genomic and Transcriptomic Characterization of IgM Multiple Myeloma Identifies a Pre-Germinal Center Plasma Cell Disorder with Immature B-Cell Transcription-Factor Signature

Blood ◽

10.1182/blood-2020-138951 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 7-8

Author(s):

Abdul Hamid Bazarbachi ◽

Herve Avet-Loiseau ◽

Zachary R Hunter ◽

Raphael Szalat ◽

Anil Aktas-Samur ◽

...

Keyword(s):

Multiple Myeloma ◽

B Cell ◽

Board Of Directors ◽

Research Funding ◽

Switch Region ◽

Publicly Traded ◽

Private Company ◽

Advisory Committees ◽

Transcript Levels ◽

Unique Signature

Multiple myeloma (MM) is a proliferation of terminally differentiated plasma cells (PC) producing monoclonal immunoglobulins (Ig), most commonly IgG and IgA (50% and 25% respectively), and less frequently, light-chain only disease, non-secretory, and IgD. IgM-MM is a rare entity (<0.5%), and its differentiation from common IgM producing PC disorders like Waldenström's macroglobulinemia (WM) is essential considering their distinct treatments and prognoses. Recent advancements in molecular techniques have shed light on the genomic characteristics and unique alterations in MM and WM, however, comprehensive profiling is still lacking for IgM-MM. We performed deep whole-genome sequencing on five IgM samples as well as 211 MM and 34 WM samples, and transcriptome sequencing on the IgM samples as well as 30 MM, 35 WM, and 3 PC. All IgM-MM samples harbored t(11;14) which combines super enhancers in Ig genes with CCND1. All translocations involved VHDHJH regions (Figure 1A) at the immunoglobulin heavy chain (IGH) locus, compared to IgG/IgA MM samples that had predominantly switch-region translocations (Figure 1B/C). Switch-region translocations are generated through class-switch recombination (CSR) in mature B-cells in germinal centers (GC), and VHDHJH translocations occur during recombination at the early pro-B-cell stage in the bone marrow (BM). While IgG/IgA-MM displayed evidence of CSR with deletions between IGHM switch-region and IGHG/IGHA switch regions, IgM-MM had no such events. IgM-MM therefore appears to undergo malignant transformation prior to late-stage B-cell maturation, after which CSR is unlikely, which is supported by a lack of progression of IgM-monoclonal gammopathy of undetermined significance (MGUS) to non-IgM-MM. IgM-MM also displayed similar copy number variation (CNV) patterns and driver mutations compared to non-IgM-MM suggesting similar progression events. Unsupervised hierarchical clustering using differentially expressed genes between non-IgM-MM and WM separated the IgM-MM samples within non-IgM-MM. This indicates a closer molecular homology to MM compared to WM with a unique signature for this group not accounted for by the t(11;14) translocation. Running the same analysis using only B-cell specific transcription factors (TFs) yielded similar results, with separation of WM and MM and preferential clustering of IgM-MM within the latter while also exhibiting a unique signature (Figure 1D). Some noteworthy examples were the upregulation of PBX3, PAX5, BCL11A, and ATF2, and the downregulation of PRDM1 and BCL3 compared to non-IgM-MM. The loss of PAX5 and upregulation of PRDM1 in B-cells has been implicated in promoting commitment to PC differentiation, while BCL11A was found essential for early B-cell progenitor development through the GC but extinguished in terminally differentiated PC. It appears that IgM-MM has therefore a more immature phenotype compared with non-IgM-MM, which further supports the previously discussed findings of its pre-GC origin and lack of terminal development. Three clinically relevant targets were noted to be upregulated in IgM-MM, Bruton's tyrosine kinase (BTK), CD20 and BCL-2. BTK was significantly higher in IgM-MM compared to non-IgM-MM (log2fold=1.3; FDR<10-3) with no difference between IgM-MM and WM (log2fold =-0.4; FDR>0.2). This could elucidate a more prominent role for BTK-inhibition in the IgM-MM subgroup. Furthermore, as documented in t(11;14)-MM, IgM-MM had elevated transcript levels of CD20 with possible targeting using anti-CD20 antibodies. Finally, elevated levels of BCL-2 in both IgM and non-IgM-t(11;14)-MM were observed, an established target for both single-agent and combination therapy. Interestingly, although not significant, IgM-MM had lower transcript levels of BCL-XL and MCL-1 compared to non-IgM-t(11;14)-MM, believed to be a predictor of higher sensitivity to venetoclax, and therefore an important guide for treatment choice. Clinical data however is lacking, and further investigations are needed to fully understand the potential role of these drugs in treating IgM-MM. In summary we describe a unique genomic and transcriptomic profile of IgM-MM, compared to both non-IgM-MM and WM, that describes its cellular origin and provides the rationale for potential therapeutic intervention. Disclosures Fulciniti: NIH: Research Funding. Anderson:Gilead: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Sanofi-Aventis: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Millenium-Takeda: Membership on an entity's Board of Directors or advisory committees; Oncopep and C4 Therapeutics.: Other: Scientific Founder of Oncopep and C4 Therapeutics.. Parmigiani:Phaeno Biotehnologies: Current equity holder in publicly-traded company; CRA Health: Current equity holder in publicly-traded company; Foundation Medicine Institute: Consultancy; Delphi Diagnostics: Consultancy; BayesMendel Laboratory: Other: Co-lead. Treon:Bristol-Meyer-Squibb: Honoraria, Research Funding; Pharmacyclics: Honoraria, Research Funding. Mohty:Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau; GSK: Consultancy, Honoraria, Research Funding, Speakers Bureau; BMS: Consultancy, Honoraria, Research Funding, Speakers Bureau; Stemline: Consultancy, Honoraria, Research Funding, Speakers Bureau; Jazz Pharmaceuticals: Consultancy, Honoraria, Research Funding, Speakers Bureau; Sanofi: Consultancy, Honoraria, Research Funding, Speakers Bureau; Takeda: Consultancy, Honoraria, Research Funding, Speakers Bureau; Amgen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau. Munshi:Takeda: Consultancy; BMS: Consultancy; OncoPep: Consultancy, Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties; C4: Current equity holder in private company; Janssen: Consultancy; Adaptive: Consultancy; Legend: Consultancy; Amgen: Consultancy; Karyopharm: Consultancy; AbbVie: Consultancy.

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Patterns of Venetoclax Sensitivity in Chronic Lymphocytic Leukemia

Blood ◽

10.1182/blood-2020-137674 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 12-14

Author(s):

James T Dibb ◽

Nicola Long ◽

Christopher A. Eide ◽

Stephen E Kurtz ◽

Cristina E. Tognon ◽

...

Keyword(s):

Chronic Lymphocytic Leukemia ◽

Board Of Directors ◽

Research Funding ◽

Ex Vivo ◽

Single Agent ◽

Drug Combinations ◽

Lymphocytic Leukemia ◽

Publicly Traded ◽

Private Company ◽

Advisory Committees

Patterns of Venetoclax Sensitivity in Chronic Lymphocytic Leukemia Chronic lymphocytic leukemia (CLL) is predominantly a disease of older adults. The 5-year overall survival is 70-91%, depending on Rai/Binet stage at diagnosis (80% overall), and although a subset of CLL takes a very indolent course, it can be aggressive as well. Disease course and responsiveness to therapeutic agents may be predictable, to some degree, based on specific genetic lesions or other patient population characteristics. Monotherapies targeting specific cell pathways are rapidly increasing in prevalence. Ibrutinib (Bruton tyrosine kinase inhibitor) has shown promise as a single agent as well as in combination with other agents. In particular, ibrutinib has shown efficacy in combination with venetoclax (inhibitor of cell death suppressor BCL2). This combination appears to be particularly potent in patients with a del(11q) karyotype. Cytogenetic information is used already in several other leukemias to inform prognosis and treatment. Although CLL is a disease of monoclonal proliferation, precise definition of the diseased clone will allow for more individualized treatment. Stratification of drug sensitivity based on genetic and cytogenetic features will directly affect patient outcomes in CLL. Primary patient mononuclear cells (from either peripheral blood or bone marrow) were plated ex vivo with a panel of 49 drug combinations and the 16 respective single agents (SA) in 384-well plates using 10,000 cells/well. Drugs were tested in 7-point concentration series; wells with drug combinations were added at fixed molar ratios. Cell viability was assessed after a 72 hour culture period. In this assay, primary cells maintain viability but do not proliferate. In CLL, the most frequent mutations were: del(17p); del(11q); del(13q14); trisomy 12; complex karyotype (at least three chromosomal aberrations). Selected analysis of these data from 157 unique patients were performed by isolating the most potent inhibitors (defined by lowest median AUC) either as a single agent or in combination with known treatments. These were evaluated with nonparametric tests (Kruskal-Wallace, Mann-Whitney, Spearman rank coefficient) on the statistical software Prism. By subdividing the data by available genetic and cytogenetic information, patterns that have not been previously described in the literature emerged. In the cohort of patients with any karyotypic abnormality (not complex karyotype), SA venetoclax and the combination of venetoclax-ibrutinib (VEN/IBRUT) were equivalently effective with no significant difference in efficacy observed between SA venetoclax and the combination. As previously described, del(11q) independently predicts increased efficacy of SA venetoclax and VEN/IBRUT, and this efficacy was validated by ex vivo potency here as well. However, we show that male gender is an independent predictor of potency in both SA venetoclax and VEN/IBRUT as well. Interestingly, doramapimod (an inhibitor of p38 MAP kinase) was not particularly potent as a SA, however, the combination of venetoclax-doramapimod (VEN/DORA) proved to be the most potent of all combinations tested, more potent than even VEN/IBRUT. This effect could not be replicated in any subgroup, as VEN/DORA samples for the entire cohort were relatively limited (n=31). Although this analysis has inherent limitations, including underpowered data to analyze in less frequent cytogenetic events (e.g. del(6q)), we did find significant patterns of potency. These may or may not translate to clinical efficacy in CLL and do not address any potential toxicity. However, these data suggest future directions for more targeted research on these drugs and drug combinations. Disclosures Tyner: Petra:Research Funding;Janssen:Research Funding;Seattle Genetics:Research Funding;Incyte:Research Funding;Genentech:Research Funding;Constellation:Research Funding;AstraZeneca:Research Funding;Aptose:Research Funding;Gilead:Research Funding;Takeda:Research Funding;Syros:Research Funding;Agios:Research Funding;Array:Research Funding.Druker:EnLiven:Consultancy, Research Funding;Gilead Sciences:Consultancy, Membership on an entity's Board of Directors or advisory committees;Cepheid:Consultancy, Membership on an entity's Board of Directors or advisory committees;Dana-Farber Cancer Institute:Patents & Royalties;Bristol-Myers Squibb:Research Funding;Blueprint Medicines:Consultancy, Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees;Aptose Therapeutics Inc. (formerly Lorus):Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees;ARIAD:Research Funding;Third Coast Therapeutics:Membership on an entity's Board of Directors or advisory committees;The RUNX1 Research Program:Membership on an entity's Board of Directors or advisory committees;Pfizer:Research Funding;Patient True Talks:Consultancy;Oregon Health & Science University:Patents & Royalties;Novartis Pharmaceuticals:Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding;MolecularMD (acquired by ICON):Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees;Millipore (formerly Upstate Biotechnology):Patents & Royalties;VB Therapeutics:Membership on an entity's Board of Directors or advisory committees;Vivid Biosciences:Membership on an entity's Board of Directors or advisory committees;ALLCRON:Consultancy, Membership on an entity's Board of Directors or advisory committees;Amgen:Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees;Aileron Therapeutics:Membership on an entity's Board of Directors or advisory committees;Merck & Co:Patents & Royalties;McGraw Hill:Patents & Royalties;GRAIL:Consultancy, Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees;Henry Stewart Talks:Patents & Royalties;Iterion Therapeutics (formerly Beta Cat Pharmaceuticals):Membership on an entity's Board of Directors or advisory committees;Leukemia & Lymphoma Society:Research Funding.

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Bone Pain As a Presenting Symptom in Patients with Newly Diagnosed Multiple Myeloma in the Primary Care Setting: A Population-Based Cohort Study

Blood ◽

10.1182/blood-2020-138819 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 18-18

Author(s):

Anouchka Seesaghur ◽

Natalia Petruski-Ivleva ◽

Victoria Banks ◽

Jocelyn Ruoyi Wang ◽

Pattra Mattox ◽

...

Keyword(s):

Primary Care ◽

Renal Impairment ◽

Board Of Directors ◽

Clinical Features ◽

Research Funding ◽

Bone Pain ◽

Care Setting ◽

Publicly Traded ◽

Private Company ◽

Advisory Committees

Background: Diagnosing multiple myeloma (MM) is challenging, because MM can present with a myriad of non-specific signs and symptoms, such as bone pain, fatigue, fractures, infection, within an elderly patient population (median age of MM diagnosis is 70 years). Patients with MM therefore experience significant delays in diagnosis, resulting in increased morbidity and reduced survival. In the primary care setting, the presence of bone pain in combination with laboratory abnormalities, such as hypercalcaemia or unexplained renal impairment, have a critical diagnostic role in MM. However, the occurrence of these clinical features prior to MM diagnosis within a population-based incident cohort of patients with MM has not been previously well described. Aims: To describe the frequency and timing of the initial clinical features among patients with newly diagnosed MM (NDMM) in the UK primary care setting. Methods: We used Clinical Practice Research Datalink (CPRD), an electronic health records database, derived from routinely collected general practitioner (GP) data across the UK primary care, containing approximately 17.1 million patients at the time of analysis. We identified patients with NDMM (2006-2016), aged ≥18 years with no history of solid tumors, and ≥2 years of GP registration prior to MM diagnosis. Baseline clinical characteristics were assessed during the 2-year period before MM diagnosis. We assessed clinical features, including bone pain, skeletal-related events (SREs) and CRAB criteria (hyperCalcemia, Renal failure, Anemia, Bone lesions) for MM during the 2-year period before MM diagnosis and from the time of symptom presentation or relevant diagnostic CRAB criteria to the diagnosis of MM. Results: We identified 2,646 eligible patients with NDMM with a median [Q1, Q3] age of 70 [61, 77]; 53.3% of patients were male. During the 2-year period prior to MM diagnosis, 47.5% of patients had a record of bone pain, mainly affecting the back or other joints, and 4.8% had a record of SRE. The median time between the first record of bone pain and MM diagnosis was 220 days. Regardless of recorded bone pain, laboratory investigations for hypercalcaemia, renal impairment, and anaemia and were conducted in 36.4%, 74.2%, 65.6% and of patients prior to MM diagnosis, respectively. Approximately 5.5% of patients presented with hypercalcemia, 13.5% with renal impairment and 31.3% with anemia. The median time from the first-recorded hypercalcaemia, renal impairment or anaemia event to MM diagnosis was 23, 58 and 73 days, respectively. An imaging investigation or referral for an imaging investigation was recorded for approximately 60% of patients with bone pain/SRE and 32% without bone pain/SRE. One out of five patients with bone pain/SRE and imaging investigations had a record of magnetic resonance imaging or computed tomography scan (Table 1). Conclusions: Nearly half of patients with newly diagnosed MM presented with a bone pain symptom in primary care, approximately 7 months prior to MM diagnosis. Investigations for hypercalcaemia were not frequent in patients presenting with bone pain, and tests to explore CRAB criteria were underutilized. Underuse of targeted imaging in patients presenting with bone pain was observed. Early recognition and testing for clinical features of MM in primary care may potentially expedite the disease diagnosis and lead to timely medical care. Disclosures Seesaghur: Amgen (Europe) GmbH: Current Employment, Current equity holder in publicly-traded company. Petruski-Ivleva:Aetion: Current equity holder in private company, Ended employment in the past 24 months. Banks:Amgen (Europe) GmbH: Ended employment in the past 24 months, Other: Contract worker at Amgen during the conduct of the study. Wang:Aetion: Current Employment, Current equity holder in private company. Mattox:Aetion: Current Employment, Current equity holder in private company. Abbasi:Amgen (Europe) GmbH: Other: Contract worker at Amgen. Maskell:Amgen (Europe) GmbH: Current Employment, Current equity holder in publicly-traded company. Neasham:Amgen (Europe) GmbH: Current Employment, Current equity holder in publicly-traded company. Ramasamy:Takeda: Honoraria; Janssen: Honoraria; Janssen: Research Funding; Takeda: Research Funding; Sanofi: Honoraria; Amgen: Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Honoraria; Oncopeptides: Honoraria; Takeda: Speakers Bureau; Bristol Myers squibb: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Research Funding; Amgen: Honoraria; GSK: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Membership on an entity's Board of Directors or advisory committees.

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Real-World Treatment of Pediatric Patients with Relapsed/Refractory B-Cell Acute Lymphoblastic Leukemia Using Tisagenlecleucel That Is out of Specification for Commercial Release

Blood ◽

10.1182/blood-2020-136674 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 42-44

Author(s):

Jenna Rossoff ◽

Christina Baggott ◽

Snehit Prabhu ◽

Holly Pacenta ◽

Christine L Phillips ◽

...

Keyword(s):

B Cell ◽

Board Of Directors ◽

Real World ◽

Research Funding ◽

Lymphoblastic Leukemia ◽

Single Patient ◽

Publicly Traded ◽

Private Company ◽

Advisory Committees ◽

Car T

Introduction Chimeric antigen receptor (CAR) T cell therapy has been extremely efficacious in pediatric patients with multiply relapsed and/or refractory B-cell acute lymphoblastic leukemia (B-ALL) with overall remission rates of 81% by three months post-infusion (Maude et al., N Engl J Med, 2018), and achieved FDA approval for this indication. In order for the product to meet the standards of this approval for commercial release, both the leukapheresis and manufactured products must meet a variety of specific requirements, some of which are more stringent than those in these pivotal clinical trials. The Managed Access Program (MAP) provides access to tisagenlecleucel for patients with B-ALL or diffuse large B-cell lymphoma that is out of specification (OOS) for whom repeat leukapheresis is not feasible. Patients may also receive OOS tisagenlecleucel by applying for a single-patient Investigational New Drug (IND). Previous reports have shown no difference in efficacy or toxicity between patients receiving tisagenlecleucel that meets commercial release specifications and those receiving OOS tisagenlecleucel (Grupp, et al., Blood Abstr 614, 2019; Jaglowski, et al., Blood Abstr 627, 2019). This study seeks to evaluate outcomes in pediatric and young adult patients who received tisagenlecleucel via the MAP or a single-patient IND in our Pediatric Real World CAR Consortium (PRWCC). Methods Retrospective data were abstracted from the PRWCC database of patients with relapsed/refractory B-ALL from fifteen different US institutions who received tisagenlecleucel as an FDA-approved therapy outside the context of a clinical trial. Patients whose cellular product was obtained through the MAP (NCT03601442) or with single patient IND approval due having either a cryopreserved leukapheresis product and/or manufactured tisagenlecleucel that did not meet specifications for commercial release were categorized as MAP/IND and those whose product met all release criteria were categorized as standard of care (SOC). Results Among 185 total infused patients in our database, 24 (13%) received tisagenlecleucel either via the MAP (n=14) or a single patient IND (n=10). Baseline patient and disease characteristics were not significantly different for MAP/IND patients versus the SOC cohorts (Table 1). Median duration of follow-up post-CAR T cell infusion for these infused patients was 342.5 days (range 107-780) versus 318 days (range 6-863) for the SOC cohort (p=0.43). Reasons for products being OOS included cell viability <80% (n=17), total nucleated cell count <2x109 in leukapheresis product (n=3), failed interferon gamma release assay (n=2), cryopreserved leukapheresis product collected >9 months prior (n=1), and determination of residual beads >50 beads/3x106cells (n=1). Overall survival at 6- and 12-months was 96% versus 83% and 85% versus 70% for the MAP/IND versus SOC, respectively. Event-free survival at 6- and 12-months was 65% versus 63% and 55% versus 51%, respectively. Probability of continued remission at 6- and 12-months among patients who achieved a complete remission (CR) at day 28 was 79% versus 75% and 66% versus 63% for the MAP/IND versus SOC, respectively (Figure 1). Comparing toxicities between patients in the MAP/IND versus SOC cohorts, cytokine release syndrome (CRS, any grade) occurred in 46% versus 61%, CRS (>grade 3) in 17% versus 19%, immune effector cell-associated neurotoxicity syndrome (ICANS) in 8% versus 22%, and infectious complications in 54% vs. 37%, respectively (p=ns for all). Conclusions In our retrospective cohort evaluating the use of tisagenlecleucel to treat pediatric and young adult patients with relapsed/refractory B-ALL in the real-world setting, neither the efficacy nor safety of tisagenlecleucel seem to be compromised by use of products OOS for commercial release. Larger studies are needed to further delineate specific cut-offs outside of which either efficacy and/or safety may truly be impacted. Disclosures Phillips: Novartis: Membership on an entity's Board of Directors or advisory committees. Stefanski:Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Margossian:Novartis: Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees. Verneris:Novartis: Membership on an entity's Board of Directors or advisory committees; Fate Therapeutics: Consultancy, Current equity holder in publicly-traded company; Bmogen: Consultancy, Current equity holder in publicly-traded company; Uptodate: Consultancy. Myers:Novartis: Consultancy, Honoraria, Other: ELIANA trial Steering Committee, Speakers Bureau. Brown:Janssen: Membership on an entity's Board of Directors or advisory committees; Servier: Membership on an entity's Board of Directors or advisory committees; Jazz: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Qayed:Mesoblast: Consultancy; Novartis: Consultancy. Hermiston:Novartis: Membership on an entity's Board of Directors or advisory committees; Sobi: Membership on an entity's Board of Directors or advisory committees. Satwani:Mesoblast: Consultancy; Takeda: Consultancy. Curran:Novartis: Consultancy, Research Funding; Celgene: Research Funding; Mesoblast: Consultancy. Mackall:Apricity Health: Consultancy, Current equity holder in private company; Lyell Immunopharma: Consultancy, Current equity holder in private company; BMS: Consultancy; Nektar Therapeutics: Consultancy; Allogene: Current equity holder in publicly-traded company; NeoImmune Tech: Consultancy. Laetsch:Novartis: Consultancy, Research Funding; Bayer: Research Funding; Pfizer: Research Funding; Cellectis: Consultancy.

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High-Dose Melphalan Significantly Increases Mutational Burden in Multiple Myeloma Cells at Relapse: Results from a Randomized Study in Multiple Myeloma

Blood ◽

10.1182/blood-2020-139014 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 4-5

Author(s):

Mehmet K. Samur ◽

Marco Roncador ◽

Anil Aktas-Samur ◽

Mariateresa Fulciniti ◽

Abdul Hamid Bazarbachi ◽

...

Keyword(s):

Multiple Myeloma ◽

Board Of Directors ◽

Research Funding ◽

High Dose ◽

Publicly Traded ◽

Private Company ◽

Advisory Committees ◽

High Dose Melphalan ◽

New Mutations

We recently shown that high-dose melphalan (HDM) followed by autologous stem cell transplant (ASCT) as first line therapy in young (<66 yrs) multiple myeloma (MM) patients significantly improves progression-free survival (IFM/DFCI 2009 study). However, the impact of alkylating agent melphalan inducing N-alkylpurine-monoadducts forming interstrand crosslinks (ICLs) in surviving myeloma cells remains an important biological question. We here profiled samples from the IFM/DFCI 2009 study, where patients were randomized to RVD+HDM vs RVD alone, to identify genomic changes induced by HDM and observed at relapse. We analyzed paired purified MM cells collected at diagnosis and at relapse from 68 patients using deep (75X) whole genome sequencing. Forty-five patients were treated with RVD only, while 23 patients received RVD followed by HDM. There was no significant difference between the 2 groups in regard to disease characteristics including sex, age, cytogenetic risk, and best response. Median follow-up was similar (29 vs 31 months, respectively), removing longer follow up as a confounding variable. The number of mutations at diagnosis was similar on both arms (7137 [IQR=3742] vs. 7230 [IQR=3702], p value = 0.67). Although mutational load increased in both arms; there was a significantly higher increase in number of mutations and indels in the HDM arm compared to RVD alone (mutations 5686 vs 1745, p=1.4e-5; and indels 467 vs 360, p= 0.02, respectively). Using a model incorporating number of new mutations, depth, and purity, we found that HDM causes a 4.1 fold higher mutation accumulation rate per month than RVD only (158.3 vs 38.3 mutations/ month; p=0.003). Importantly, newly acquired mutations were localized to regions which overlap with transcribed regions, and accumulated at significantly higher rate in the HDM group (p=0.009). In contrast, we did not observe any significant changes in copy number alterations (CNAs) and structural variants, including translocations, between both arms. A significant change in frequency of driver mutations including RAS/RAF, FAM46C, TP53, and DIS3 was not observed at the time of relapse. Clonality level was increased only for KRAS (p=0.054), while all other specific driver genes had similar clonality level at diagnosis and relapse. Interestingly, a significant increase in mutations involving MYO16 and SLC7A8 genes was observed at relapse in both arms, implicating components of the induction regimen (RVD). Investigating the mutational signature utilization in only newly acquired mutations identified 4 signatures: APOBEC, HR Double Strand Repair, clock-like signature, and unknown. k-means clustering analysis of samples based on signature utilization showed four distinct clusters. All patients clustering with high DNA repair signature utilization were in the HDM arm (65% HDM patients), the majority of whom achieved CR or sCR (74%); these patients acquired 8308 (range 3302-19107) new mutations between diagnosis and relapse. None of the RVD only treated patients were in this cluster. The remaining 35% HDM group patients were clustered with RVD samples and showed unknown signature utilization. Furthermore, motif enrichment analysis identified CYWR and ATGAGATV (p < 1e-130) as enriched motifs around the new mutations in HDM compared to RVD cohort. Importantly and as expected, DNA damage repair pathway genes were frequently targeted in the HDM group: 72% HDM samples accumulated DDR gene mutations vs. only 17% in the RVD alone arm (p < 0.001). At the time of relapse, 100% HDM arm patients had at least one DDR gene mutation and 80% had two or more, while only 37% RVD only group had one or more such mutation. Finally, we have reconstructed phylogenetic and evolutionary trajectories based on mutation and copy-number data from samples at diagnosis and relapse. The clonal composition in both arms was similar at diagnosis; however, HDM caused a significant shift to more subclonal mutations at relapse. chromothripsis and chromoplexy events were detected in 30% patients at diagnosis, which remained constant at relapse regardless of treatment. In summary, we describe significant accumulation of mutations following high dose melphalan. This fundamental molecular change in the disease at relapse, suggests the need for reappraisal of the optimal use and sequencing of high dose melphalan in the era of novel agents. Disclosures Fulciniti: NIH: Research Funding. Richardson:Celgene/BMS, Oncopeptides, Takeda, Karyopharm: Research Funding. Thakurta:Oxford University: Other: visiting professor; Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Perrot:Amgen, BMS/Celgene, Janssen, Sanofi, Takeda: Consultancy, Honoraria, Research Funding. Moreau:Sanofi: Consultancy, Honoraria; Celgene/Bristol-Myers Squibb: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Honoraria; Novartis: Honoraria; Abbvie: Consultancy, Honoraria; Amgen: Consultancy, Honoraria. Anderson:Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Oncopep and C4 Therapeutics.: Other: Scientific Founder of Oncopep and C4 Therapeutics.; Sanofi-Aventis: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Millenium-Takeda: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees. Parmigiani:Phaeno Biotehnologies: Current equity holder in publicly-traded company; CRA Health: Current equity holder in publicly-traded company; Foundation Medicine Institute: Consultancy; Delphi Diagnostics: Consultancy; BayesMendel Laboratory: Other: Co-lead. Munshi:Amgen: Consultancy; AbbVie: Consultancy; Karyopharm: Consultancy; Takeda: Consultancy; Adaptive: Consultancy; Janssen: Consultancy; C4: Current equity holder in private company; OncoPep: Consultancy, Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties; BMS: Consultancy; Legend: Consultancy.

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