Gemtuzumab in Children with Relapsed and Refractory Acute Myeloid Leukemia Treated on Compassionate-Use Basis: A Report of the AML-BFM Study Group

Abstract BACKGROUND: Long-term survival in pediatric acute myeloid leukemia (AML) improved remarkably during the last decades. However, children with refractory disease or relapsed AML still suffer from exceedingly poor outcome, especially those who relapse within one year of diagnosis with very limited treatment options. Gemtuzumab ozogamicin (GO) is an anti-CD33 antibody linked to calicheamicin, a potent cytotoxic agent. Developed for targeted treatment of CD33-positive AML, studies in adults showed its efficacy in relapsed and refractory AML. We performed this retrospective analysis of patients with highly advanced pediatric AML, receiving GO as compassionate use. PATIENTS AND METHOD: In total, 96 children <18 years diagnosed from 1995 to 2014 with multiple relapsed or refractory AML received GO as compassionate use. Eighty-eight patients had sufficient data available for this retrospective analysis, evaluation of adverse effects during first cycle of GO was based on medical reports of 83 patients. Sixty-one patients were treated in refractory disease or early first relapse, but also including 7 patients with 2 relapses within the first year after diagnosis. Nine patients were in 2nd relapse (>1year from diagnosis) and one patient in 3rdrelapse, four children had AML as secondary malignancy. Fourteen children have been already transplanted once, one child twice before GO therapy. Fourty-seven children received monotherapy with GO, 35 children were treated combined with cytarabine and 3 children received other combinations with other agents (3 unknown). Fifty-three patients received one cycle, 34 received 2 cycles of GO, however one patient received 4 cycles of monotherapy. Of note, eight patients have been previously reported elsewhere (Zwaan et al., Br J Haematol. 2010). Time of database lock was 07/2016 with a median follow-up of 9.8 years for the surviving patients. RESULTS: Safety profile was comparable to other pediatric studies. Adverse effects during first cycle of treatment consisted mostly of fever in neutropenia (n=49), less frequently infections (n=9) or allergic reactions (n=18). A few patients reported about mild gastrointestinal symptoms, which was not clearly related to GO due to combination therapy. Two patients suffered from sepsis. Veno-occlusive disease (VOD) of the liver occurred in three patients, one of those had a previous VOD, but all of them have been treated successfully with defibrotide. No lethal event was observed during treatment with GO. One patient developed a VOD during subsequent transplantation despite of prophylactic use of defibrotide. Sixty patients were evaluable for response assessment of the bone marrow. Twenty-eight children showed a response with a blast reduction to 5% or less in the bone marrow samples after treatment (46%). Fourteen out of these patients, received GO combined with cytarabine, 12 patients had monotherapy, and two other combinations. Subsequently, 53 children proceeded to stem cell transplantation (SCT) (one patient unknown). Of note, 13 out of those, received further chemotherapy before HSCT was performed. In details, 47 patients proceeded to first SCT, whereas 5 patients received 2ndSCT (one unknown). Time to transplantation varied (<3 weeks, n=14; 3 to 6 weeks, n=28; >6 weeks, n=11 patients [median time to transplantation after GO: 30 days]). The probability of 4-year overall survival after treatment with GO of all patients (n=88) was 21±4%. In patients treated with monotherapy it was 18±6%. Eighteen patients of this cohort are still alive at time of database lock. CONCLUSION: To our knowledge, this analysis is the largest pediatric cohort of patients, treated with GO in a very advanced disease. The results of this retrospective trial indicate efficacy of GO, while having an acceptable toxicity profile, even in heavily pretreated patients. It can induce blast reduction and even survival in patients, who have no further conventional treatment options. Further randomized studies are necessary to learn more about efficacy and side effects in a relapse setting, especially for therapeutic implications in future. Disclosures Rasche: Jazz Pharma: Other: Travel accomodation. Zwaan:Pfizer: Research Funding; Pfizer: Consultancy. Reinhardt:Pfizer: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Boehringer Ingelheim: Membership on an entity's Board of Directors or advisory committees; Celgene: Research Funding; Jazz Pharma: Other: Travel Accomodation.

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Preliminary Results from a Phase 1 Study of Cfi-400495, a PLK4 Inhibitor, in Patients with Acute Myeloid Leukemia and High Risk MDS

Blood ◽

10.1182/blood-2020-138822 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 1-2

Author(s):

Tracy Murphy ◽

Brian Leber ◽

Mark R Bray ◽

Steven M Chan ◽

Vikas Gupta ◽

...

Keyword(s):

Bone Marrow ◽

Board Of Directors ◽

Myeloid Leukemia ◽

Research Funding ◽

Phase 1 ◽

Single Agent ◽

Advisory Committees ◽

Once Daily ◽

Acute Myeloid ◽

Refractory Aml

Introduction: CFI-400945 is a first-in-class, potent, selective, orally active inhibitor of Polo-like kinase 4 (PLK4) (Ki=0.26nM), a master regulator of centriole duplication, necessary for genomic integrity (Mason et al. Cancer Cell 2014; 26:163-76). CFI-400945 has activity in leukemia cell lines and primary leukemia samples including those with complex karyotype, inversion 3 and monosomy 7 (Minden. personal communications). This suggests that CFI-400945 may provide an effective treatment of patients with AML. The objectives of this phase 1 trial was to establish the safety, tolerability, and recommend phase II dose (RP2D) of CFI-400945 in patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). Methods: Patients with relapsed/refractory AML or MDS and patients with untreated AML who refused induction chemotherapy or who are not candidates for intensive chemotherapy were eligible. Dose escalation followed a standard 3+3 design with a starting dose of 64 mg orally once daily. Plasma levels of CFI-400945 free base were measured on Days 1, 2, & 29 of Cycle 1 and Day 15 on all subsequent cycles. Peripheral blood and/or bone marrow were obtained at baseline, Day 8 of Cycle 1 and Day 1 of each subsequent cycle prior to dosing for pharmacodynamic monitoring. Safety assessments using the NCI CTCAE version 4.03 were performed. Results: From May 2018 to June 2019, nine patients have been enrolled on study across three pre-defined dose levels (64 mg [n=3], 96 mg [n=4], and 128 mg [n=2]). Three patients had untreated AML, five patients had relapsed/refractory AML and one patient had myelodysplastic syndrome/myeloproliferative disorder (MDS/MPN). Patient characteristics at diagnosis are outlined in Table 1. Six (67%) patients had baseline high throughput sequencing; the most frequent mutations were TP53 (33%), TET2 (33%), KRAS (33%) and DNMT3A (33%). A total of 20 cycles were administered with a median of 1 cycle (range, 0 to 7 cycles). The most common non-hematological drug related toxicities of any grade, which occurred in over 20%, were diarrhea (44%), headache (44%), colitis (33%), vomiting (33%), bilirubin increase (22%), dizziness (22%), fatigue (22%), and nausea (22%). One patient on the 96 mg dose level was not evaluable for DLT and hence, replaced. Both patients treated at the 128 mg/day dose level developed DLTs, consisting of grade 3 colitis and grade 5 sepsis and colitis. Pharmacokinetic profile indicated low interpatient variability between patients. Maximum exposure did not correlate with toxicity Six patients were evaluable for disease response. Two (33%) achieved complete remission (CR), 3 pts (50%) had stable disease (with one patient having a 78% reduction in marrow blast count). The patient with MDS/MPN who did not complete 1 cycle of therapy progressed to AML (Figure 1). Both patients who obtained a CR had an early response within 2 cycles. One CR has been durable for 218 days with no measurable residual disease (MRD) by flow cytometry. The additional patient, who obtained a CR with incomplete platelets recovery, with subsequent best response of CR, had a sustained response for 91 days before relapse was confirmed by bone marrow examination (Figure 1). Conclusion: Single agent CFI-400945 has activity in patients with poor risk AML. The RP2D in this population is 96 mg once daily. Dose expansion is occurring at the RP2D level. A phase 2 study with CFI-400945 single agent or in combination study with azacitidine or decitabine is planned. Disclosures Leber: Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Alexion: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Lundbeck: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda/Palladin: Honoraria, Membership on an entity's Board of Directors or advisory committees; Treadwell: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS/Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Otsuka Pharmaceutical: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees. Bray:Treadwell Therapeutics: Current Employment; TIO Discovery: Current Employment. Gupta:Pfizer: Consultancy; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Sierra Oncology: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bristol MyersSquibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Honoraria, Research Funding. Maze:Novartis: Honoraria; Pfizer: Consultancy; Takeda: Research Funding. McNamara:Novartis: Honoraria. Schimmer:Jazz: Honoraria; Otsuka: Honoraria; Medivir AB: Research Funding; AbbVie Pharmaceuticals: Other: owns stock ; Takeda: Honoraria, Research Funding; Novartis: Honoraria.

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Safety and Tolerability of Lurbinectedin (PM01183) in Patients with Acute Myeloid Leukemia and Myelodysplastic Syndrome

Blood ◽

10.1182/blood-2018-99-115673 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 2722-2722

Author(s):

Kelly S. Chien ◽

Christopher B. Benton ◽

Ayalew Tefferi ◽

José Rodríguez ◽

Farhad Ravandi ◽

...

Keyword(s):

Clinical Trial ◽

Bone Marrow ◽

Board Of Directors ◽

Myeloid Leukemia ◽

Research Funding ◽

Advisory Committees ◽

Genetics Research ◽

Grade 3 ◽

Acute Myeloid ◽

Refractory Aml

Abstract Background: Trabectedin is an FDA-approved DNA minor groove binder (MGB) that has activity against translocation-associated sarcomas. Lurbinectedin is a next-generation MGB with pre-clinical activity against myeloid leukemia cells. A dose-finding phase 1 clinical trial was performed in patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) with further assessment of safety and tolerability. Methods: Forty-two patients with relapsed/refractory AML/MDS received lurbinectedin administered as a 1-hour intravenous infusion in a 3+3 study design. Two dosing schedules were used: 3.5 mg, 5 mg, 7 mg, or 6 mg on days 1 and 8 or 2 mg, 3 mg, 1 mg, or 1.5 mg for 3 consecutive days on days 1 to 3. Patients 18 years or older with a diagnosis of advanced, relapsed/refractory AML (non-acute promyelocytic leukemia) and MDS were eligible and treated on study. Eligible patients had adequate hepatic, renal, and cardiac function and an Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2. Patients with uncontrolled infection, human immunodeficiency virus, cardiac and neurological disorders, or those who were pregnant were ineligible. Clinical trial information: NCT01314599. Results: Three patients experienced dose-limiting toxicities of rhabdomyolysis (grade 4), hyperbilirubinemia (grade 3), and oral herpes (grade 3) with the days 1 and 8 schedule. Otherwise, adverse events mainly consisted of gastrointestinal manifestations (n=11), febrile neutropenia/infections (n=4), pulmonary toxicity (n=2), and renal failure (n=2). The most common laboratory abnormalities observed were an increase in creatinine (93%) and anemia, neutropenia, and thrombocytopenia (100%). Overall, 33 of 42 patients (79%) had reduction in blasts in peripheral blood or bone marrow. One patient achieved a partial response and two patients a morphologic leukemia-free state. Most (n=30, 71%) were discontinued due to progressive disease. Early deaths occurred from disease-related causes that were not attributable to lurbinectedin. Four patients with a chromosome 11q21-23 abnormality had significantly greater bone marrow blast reduction than those without such abnormality, with decrease of 31±14% (n=4) vs. 8±8% (n=16), respectively (P=0.04). Conclusions: Overall, lurbinectedin was safe and tolerated using the schedules and dose levels tested. While no sustained remissions were observed, single-agent lurbinectedin was transiently leukemia suppressive for some patients. Disclosures Rodríguez: PharmaMar: Employment. Ravandi:Bristol-Myers Squibb: Research Funding; Jazz: Honoraria; Abbvie: Research Funding; Seattle Genetics: Research Funding; Abbvie: Research Funding; Amgen: Honoraria, Research Funding, Speakers Bureau; Orsenix: Honoraria; Seattle Genetics: Research Funding; Astellas Pharmaceuticals: Consultancy, Honoraria; Sunesis: Honoraria; Orsenix: Honoraria; Macrogenix: Honoraria, Research Funding; Astellas Pharmaceuticals: Consultancy, Honoraria; Jazz: Honoraria; Xencor: Research Funding; Bristol-Myers Squibb: Research Funding; Amgen: Honoraria, Research Funding, Speakers Bureau; Macrogenix: Honoraria, Research Funding; Xencor: Research Funding; Sunesis: Honoraria. Daver:Sunesis: Consultancy; Alexion: Consultancy; Daiichi-Sankyo: Research Funding; BMS: Research Funding; ImmunoGen: Consultancy; Kiromic: Research Funding; Incyte: Research Funding; Pfizer: Consultancy; Incyte: Consultancy; ARIAD: Research Funding; Karyopharm: Consultancy; Pfizer: Research Funding; Karyopharm: Research Funding; Novartis: Consultancy; Sunesis: Research Funding; Novartis: Research Funding; Otsuka: Consultancy. Jain:Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; ADC Therapeutics: Research Funding; Infinity: Research Funding; Pfizer: Research Funding; Novimmune: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Research Funding; Servier: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Research Funding; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Genentech: Research Funding; ADC Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologioes: Research Funding; Pharmacyclics: Research Funding; Incyte: Research Funding; Verastem: Research Funding; Seattle Genetics: Research Funding; Pharmacyclics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Astra Zeneca: Research Funding; Astra Zeneca: Research Funding; Servier: Research Funding; Celgene: Research Funding; Seattle Genetics: Research Funding; Verastem: Honoraria, Membership on an entity's Board of Directors or advisory committees; Astra Zeneca: Honoraria, Membership on an entity's Board of Directors or advisory committees; Infinity: Research Funding; Adaptive Biotechnologies: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Research Funding; Cellectis: Research Funding; ADC Therapeutics: Research Funding; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologioes: Research Funding; Pharmacyclics: Research Funding; Cellectis: Research Funding; Verastem: Research Funding; Servier: Research Funding; Abbvie: Research Funding; Incyte: Research Funding; Genentech: Research Funding; Abbvie: Research Funding; BMS: Research Funding; Astra Zeneca: Honoraria, Membership on an entity's Board of Directors or advisory committees; Verastem: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; ADC Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; Servier: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novimmune: Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees. Maiti:Celgene Corporation: Other: Research funding to the institution. Martinez:PharmaMar: Employment. Siguero:PharmaMar: Employment. Al-Kali:Novartis: Research Funding.

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p53 Mediated Bone Marrow Mesenchymal Stem Cell Expansion Supports Acute Myeloid Leukemia Development

Blood ◽

10.1182/blood-2019-127245 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 523-523

Author(s):

Rasoul Pourebrahimabadi ◽

Zoe Alaniz ◽

Lauren B Ostermann ◽

Hung Alex Luong ◽

Rafael Heinz Montoya ◽

...

Keyword(s):

Bone Marrow ◽

Board Of Directors ◽

Myeloid Leukemia ◽

Research Funding ◽

Osteoblast Differentiation ◽

Hematopoietic Cells ◽

Advisory Committees ◽

Equity Ownership ◽

Mdm2 Inhibitor ◽

Acute Myeloid

Acute myeloid leukemia (AML) is a heterogeneous disease that develops within a complex microenvironment. Reciprocal interactions between the bone marrow mesenchymal stem/stromal cells (BM-MSCs) and AML cells can promote AML progression and resistance to chemotherapy (Jacamo et al., 2014). We have recently reported that BM-MSCs derived from AML patients (n=103) highly express p53 and p21 compared to their normal counterparts (n=73 p<0.0001) (Hematologica, 2018). To assess the function of p53 in BM-MSCs, we generated traceable lineage specific mouse models targeting Mdm2 or Trp53 alleles in MSCs (Osx-Cre;mTmG;p53fl/fl and Osx-Cre;mTmG;Mdm2fl/+) or hematopoietic cells (Vav-Cre;mTmG;p53fl/fl and Vav-Cre;mTmG;Mdm2fl/+). Homozygote deletion of Mdm2 (Osx-Cre;Mdm2fl/fl) resulted in death at birth and displayed skeletal defects as well as lack of intramedullary hematopoiesis. Heterozygote deletion of Mdm2 in MSCs was dispensable for normal hematopoiesis in adult mice, however, resulted in bone marrow failure and thrombocytopenia after irradiation. Homozygote deletion of Mdm2 in hematopoietic cells (Vav-Cre;Mdm2fl/fl) was embryonically lethal but the heterozygotes were radiosensitive. We next sought to examine if p53 levels in BM-MSCs change after cellular stress imposed by AML. We generated a traceable syngeneic AML model using AML-ETO leukemia cells transplanted into Osx-Cre;mTmG mice. We found that p53 was highly induced in BM-MSCs of AML mice, further confirming our findings in primary patient samples. The population of BM-MSCs was significantly increased in bone marrow Osx-Cre;mTmG transplanted with syngeneic AML cells. Tunnel staining of bone marrow samples in this traceable syngeneic AML model showed a block in apoptosis of BM-MSCs suggesting that the expansion of BM-MSCs in AML is partly due to inhibition of apoptosis. As the leukemia progressed the number of Td-Tomato positive cells which represents hematopoietic lineage and endothelial cells were significantly decreased indicating failure of normal hematopoiesis induced by leukemia. SA-β-gal activity was significantly induced in osteoblasts derived from leukemia mice in comparison to normal mice further supporting our observation in human leukemia samples that AML induces senescence of BM-MSCs. To examine the effect of p53 on the senescence associated secretory profile (SASP) of BM-MSCs, we measured fifteen SASP cytokines by qPCR and found significant decrease in Ccl4, Cxcl12, S100a8, Il6 and Il1b upon p53 deletion in BM-MSCs (Osx-Cre;mTmG;p53fl/fl) compared to p53 wildtype mice. To functionally evaluate the effects of p53 in BM-MSCs on AML, we deleted p53 in BM-MSCs (Osx-Cre;mTmG;p53fl/fl) and transplanted them with syngeneic AML-ETO-Turquoise AML cells. Deletion of p53 in BM-MSCs strongly inhibited the expansion of BM-MSCs in AML and resulted in osteoblast differentiation. This suggests that expansion of BM-MSCs in AML is dependent on p53 and that deletion of p53 results in osteoblast differentiation of BM-MSCs. Importantly, deletion of p53 in BM-MSCs significantly increased the survival of AML mice. We further evaluated the effect of a Mdm2 inhibitor, DS-5272, on BM-MSCs in our traceable mouse models. DS-5272 treatment of Osx-cre;Mdm2fl/+ mice resulted in complete loss of normal hematopoietic cells indicating a non-cell autonomous regulation of apoptosis of hematopoietic cells mediated by p53 in BM-MSCs. Loss of p53 in BM-MSCs (Osx-Cre;p53fl/fl) completely rescued hematopoietic failure following Mdm2 inhibitor treatment. In conclusion, we identified p53 activation as a novel mechanism by which BM-MSCs regulate proliferation and apoptosis of hematopoietic cells. This knowledge highlights a new mechanism of hematopoietic failure after AML therapy and informs new therapeutic strategies to eliminate AML. Disclosures Khoury: Angle: Research Funding; Stemline Therapeutics: Research Funding; Kiromic: Research Funding. Bueso-Ramos:Incyte: Consultancy. Andreeff:BiolineRx: Membership on an entity's Board of Directors or advisory committees; CLL Foundation: Membership on an entity's Board of Directors or advisory committees; NCI-RDCRN (Rare Disease Cliln Network): Membership on an entity's Board of Directors or advisory committees; Leukemia Lymphoma Society: Membership on an entity's Board of Directors or advisory committees; German Research Council: Membership on an entity's Board of Directors or advisory committees; NCI-CTEP: Membership on an entity's Board of Directors or advisory committees; Cancer UK: Membership on an entity's Board of Directors or advisory committees; Center for Drug Research & Development: Membership on an entity's Board of Directors or advisory committees; NIH/NCI: Research Funding; CPRIT: Research Funding; Breast Cancer Research Foundation: Research Funding; Oncolyze: Equity Ownership; Oncoceutics: Equity Ownership; Senti Bio: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Eutropics: Equity Ownership; Aptose: Equity Ownership; Reata: Equity Ownership; 6 Dimensions Capital: Consultancy; AstaZeneca: Consultancy; Amgen: Consultancy; Daiichi Sankyo, Inc.: Consultancy, Patents & Royalties: Patents licensed, royalty bearing, Research Funding; Jazz Pharmaceuticals: Consultancy; Celgene: Consultancy. OffLabel Disclosure: Mdm2 inhibitor-DS 5272

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EZH2 Mutations and Impact on Clinical Outcome Analyzed in 1604 Patients with Acute Myeloid Leukemia

Blood ◽

10.1182/blood-2018-99-114421 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 1528-1528

Author(s):

Sebastian Stasik ◽

Jan Moritz Middeke ◽

Michael Kramer ◽

Christoph Rollig ◽

Alwin Krämer ◽

...

Keyword(s):

Bone Marrow ◽

Acute Myeloid Leukemia ◽

Board Of Directors ◽

Myeloid Leukemia ◽

Research Funding ◽

Employment Equity ◽

Advisory Committees ◽

Mutational Status ◽

Equity Ownership ◽

Acute Myeloid

Abstract Purpose: The enhancer of zeste homolog 2 (EZH2) is a histone methyltransferase and key epigenetic regulator involved in transcriptional repression and embryonic development. Loss of EZH2 activity by inactivating mutations is associated with poor prognosis in myeloid malignancies such as MDS. More recently, EZH2 inactivation was shown to induce chemoresistance in acute myeloid leukemia (AML) (Göllner et al., 2017). Data on the frequency and prognostic role of EZH2-mutations in AML are rare and mostly confined to smaller cohorts. To investigate the prevalence and prognostic impact of this alteration in more detail, we analyzed a large cohort of AML patients (n = 1604) for EZH2 mutations. Patients and Methods: All patients analyzed had newly diagnosed AML, were registered in clinical protocols of the Study Alliance Leukemia (SAL) (AML96, AML2003 or AML60+, SORAML) and had available material at diagnosis. Screening for EZH2 mutations and associated alterations was done using Next-Generation Sequencing (NGS) (TruSight Myeloid Sequencing Panel, Illumina) on an Illumina MiSeq-system using bone marrow or peripheral blood. Detection was conducted with a defined cut-off of 5% variant allele frequency (VAF). All samples below the predefined threshold were classified as EZH2 wild type (wt). Patient clinical characteristics and co-mutations were analyzed according to the mutational status. Furthermore, multivariate analysis was used to identify the impact of EZH2 mutations on outcome. Results: EZH2-mutations were found in 63 of 1604 (4%) patients, with a median VAF of 44% (range 6-97%; median coverage 3077x). Mutations were detected within several exons (2-6; 8-12; 14-20) with highest frequencies in exons 17 and 18 (29%). The majority of detected mutations (71% missense and 29% nonsense/frameshift) were single nucleotide variants (SNVs) (87%), followed by small indel mutations. Descriptive statistics of clinical parameters and associated co-mutations revealed significant differences between EZH2-mut and -wt patients. At diagnosis, patients with EZH2 mutations were significantly older (median age 59 yrs) than EZH2-wt patients (median 56 yrs; p=0.044). In addition, significantly fewer EZH2-mut patients (71%) were diagnosed with de novo AML compared to EZH2-wt patients (84%; p=0.036). Accordingly, EZH2-mut patients had a higher rate of secondary acute myeloid leukemia (sAML) (21%), evolving from prior MDS or after prior chemotherapy (tAML) (8%; p=0.036). Also, bone marrow (and blood) blast counts differed between the two groups (EZH2-mut patients had significantly lower BM and PB blast counts; p=0.013). In contrast, no differences were observed for WBC counts, karyotype, ECOG performance status and ELN-2017 risk category compared to EZH2-wt patients. Based on cytogenetics according to the 2017 ELN criteria, 35% of EZH2-mut patients were categorized with favorable risk, 28% had intermediate and 37% adverse risk. No association was seen with -7/7q-. In the group of EZH2-mut AML patients, significantly higher rates of co-mutations were detected in RUNX1 (25%), ASXL1 (22%) and NRAS (25%) compared to EZH2-wt patients (with 10%; 8% and 15%, respectively). Vice versa, concomitant mutations in NPM1 were (non-significantly) more common in EZH2-wt patients (33%) vs EZH2-mut patients (21%). For other frequently mutated genes in AML there was no major difference between EZH2-mut and -wt patients, e.g. FLT3ITD (13%), FLT3TKD (10%) and CEBPA (24%), as well as genes encoding epigenetic modifiers, namely, DNMT3A (21%), IDH1/2 (11/14%), and TET2 (21%). The correlation of EZH2 mutational status with clinical outcomes showed no effect of EZH2 mutations on the rate of complete remission (CR), relapse free survival (RFS) and overall survival (OS) (with a median OS of 18.4 and 17.1 months for EZH2-mut and -wt patients, respectively) in the univariate analyses. Likewise, the multivariate analysis with clinical variable such as age, cytogenetics and WBC using Cox proportional hazard regression, revealed that EZH2 mutations were not an independent risk factor for OS or RFS. Conclusion EZH mutations are recurrent alterations in patients with AML. The association with certain clinical factors and typical mutations such as RUNX1 and ASXL1 points to the fact that these mutations are associated with secondary AML. Our data do not indicate that EZH2 mutations represent an independent prognostic factor. Disclosures Middeke: Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees. Rollig:Bayer: Research Funding; Janssen: Research Funding. Scholl:Jazz Pharma: Membership on an entity's Board of Directors or advisory committees; Abbivie: Other: Travel support; Alexion: Other: Travel support; MDS: Other: Travel support; Novartis: Other: Travel support; Deutsche Krebshilfe: Research Funding; Carreras Foundation: Research Funding; Pfizer: Membership on an entity's Board of Directors or advisory committees. Hochhaus:Pfizer: Research Funding; Incyte: Research Funding; Novartis: Research Funding; Bristol-Myers Squibb: Research Funding; Takeda: Research Funding. Brümmendorf:Janssen: Consultancy; Takeda: Consultancy; Novartis: Consultancy, Research Funding; Merck: Consultancy; Pfizer: Consultancy, Research Funding. Burchert:AOP Orphan: Honoraria, Research Funding; Bayer: Research Funding; Pfizer: Honoraria; Bristol Myers Squibb: Honoraria, Research Funding; Novartis: Research Funding. Krause:Novartis: Research Funding. Hänel:Amgen: Honoraria; Roche: Honoraria; Takeda: Honoraria; Novartis: Honoraria. Platzbecker:Celgene: Research Funding. Mayer:Eisai: Research Funding; Novartis: Research Funding; Roche: Research Funding; Johnson & Johnson: Research Funding; Affimed: Research Funding. Serve:Bayer: Research Funding. Ehninger:Cellex Gesellschaft fuer Zellgewinnung mbH: Employment, Equity Ownership; Bayer: Research Funding; GEMoaB Monoclonals GmbH: Employment, Equity Ownership. Thiede:AgenDix: Other: Ownership; Novartis: Honoraria, Research Funding.

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Genetic Dissection of p53 Driven Senescence of Bone Marrow Mesenchymal Cells in Acute Myeloid Leukemia

Blood ◽

10.1182/blood-2018-99-117585 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 2625-2625

Author(s):

Rasoul Pourebrahim ◽

Peter P. Ruvolo ◽

Steven M. Kornblau ◽

Carlos E. Bueso-Ramos ◽

Michael Andreeff

Keyword(s):

Bone Marrow ◽

Acute Myeloid Leukemia ◽

Board Of Directors ◽

Myeloid Leukemia ◽

Research Funding ◽

Bone Marrow Mscs ◽

Advisory Committees ◽

Equity Ownership ◽

Bone Marrow Mesenchymal Cells ◽

Acute Myeloid

Abstract Acute myeloid leukemia (AML) is a genetically heterogeneous malignancy characterized by bone marrow infiltration of abnormally proliferating leukemic blasts which results in fatal anemia, bleeding and infectious complications due to compromised normal hematopoiesis. Patients with complete remission (CR) but incomplete blood cell count recovery (CRi) have significantly shorter survival compared to CR patients. Although there is a correlation between CRi and minimal residual disease (MRD), the two variables were shown to be independent risk factors for relapse development (1). The mechanism by which AML induces bone marrow failure in patients is largely unknown. Here, we demonstrate that AML derived MSCs highly express p53 and p21 proteins and are more senescent compared to their normal age-matched controls as demonstrated by high β-galactosidase staining (figure 1. A, B&C). Emerging evidence indicates that the aging of endosteal niche cells results in lower reconstitution potential of hematopoietic stem cells (2). To functionally evaluate the effects of AML on bone marrow MSCs, we utilized a murine leukemia model of the AML microenvironment. We transplanted Osx-Cre;mTmG mice with AML cells and compared the senescence of MSCs in normal bone marrow (Figure 1.D) with AML (Figure 1.E). Consistent with our initial findings in human, AML strongly induced senescence of osteoblasts. This suggests that AML suppresses normal hematopoiesis by inducing senescence in the hematopoietic niche. To address the role of p53 signaling in senescence of MSCs we generated a traceable conditional p53 gain/loss model specifically in bone marrow MSCs using Osx-Cre;mTmG; Mdm2fl/+ and Osx-Cre;mTmG;p53fl/fl mice respectively (Figure 1.F). Deletion of p53 in bone marrow MSCs resulted in an increased population of osteoblasts (GFP+) in Osx-Cre;mTmG;p53fl/fl mice in comparison to Osx-Cre;mTmG mice suggesting that p53 loss in osteoblasts inhibits senescence of osteoblasts. In order to evaluate p53 activity after recombination of p53fl alleles in the osteoblasts, we isolated MSCs from bone marrows and analyzed the expression of p21.P21 was significantly down regulated in osteoblasts (GFP+) derived from Osx-Cre;mTmG;p53fl/fl mice whereas its expression in the hematopoietic cells from same tissue (tdTomato+) remained comparable to p53 wild type suggesting that p21 as the master regulator of senescence is regulated by p53 in bone marrow mesenchymal cells. To evaluate the effect of p53 loss in osteoblasts and its impact on hematopoietic cells, we isolated the GFP+ cells (osteoblasts) and RFP + cells (hematopoietic) by FACS. Senescent cells, non-cell autonomously, modulate the bone marrow microenvironment through the senescence-associated secretory phenotype (SASP). We analyzed the expression of fifteen SASP cytokines by QPCR. Deletion of p53 in bone marrow mesenchymal cells strongly abrogated the expression of several SASP cytokines. Interestingly several Notch target genes such as Hey1 and Hey2 were highly induced in MSCs following p53 deletion suggesting a role for Notch signaling in hematopoietic failure following AML induced MSCs senescence. Our data suggest that AML induces senescence of endosteal niche resulting in hematopoietic failure. These findings contribute to our understanding of the role of p53 in leukemia MSCs and could have broad translational significance for the treatment of hematopoietic failure in patients with AML.Chen X, et al. (2015) Relation of clinical response and minimal residual disease and their prognostic impact on outcome in acute myeloid leukemia. J Clin Oncol 33(11):1258-1264.Li J, et al. (2018) Murine hematopoietic stem cell reconstitution potential is maintained by osteopontin during aging. Sci Rep 8(1):2833. Disclosures Andreeff: Astra Zeneca: Research Funding; Daiichi-Sankyo: Consultancy, Patents & Royalties: MDM2 inhibitor activity patent, Research Funding; United Therapeutics: Patents & Royalties: GD2 inhibition in breast cancer ; Celgene: Consultancy; Eutropics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Research Funding; Oncoceutics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; SentiBio: Equity Ownership; Aptose: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Oncolyze: Equity Ownership; Jazz Pharma: Consultancy; Reata: Equity Ownership.

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Comparison of Acute Myeloid Leukemia Measurable Residual Disease Detection By Flow Cytometry in Peripheral Blood and Bone Marrow

Blood ◽

10.1182/blood-2019-127128 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 2729-2729

Author(s):

Colin D. Godwin ◽

Yi Zhou ◽

Megan Othus ◽

Carole M. Shaw ◽

Kelda M. Gardner ◽

...

Keyword(s):

Bone Marrow ◽

Board Of Directors ◽

Correlation Coefficient ◽

Myeloid Leukemia ◽

Research Funding ◽

Residual Disease ◽

Spearman Correlation ◽

Advisory Committees ◽

Measurable Residual Disease ◽

Acute Myeloid

BACKGROUND: The current recommendation against the need for bone marrow aspiration (BMA) in routine follow-of persons with acute myeloid leukemia (AML) in remission preceded the recognition that multiparameter flow cytometry (MFC) is a sensitive and specific means to detect imminent morphologic relapse. Given this recognition, we wondered whether BMA is now necessary, or if concordance between MFC results in peripheral blood (PB) and BMA is such as to make BMA unnecessary, at least for evaluation of measurable residual disease (MRD) by MFC. Previous studies have demonstrated a strong correlation between disease detection by MFC in PB and BMA. Here we examined 724 paired PB and BMA samples from 482 patients to further examine the concordance between PB and BMA blast detection by MFC, particularly among patients in morphologic remission. PATIENTS AND METHODS: We included adults in our institutional AML database, covering 2008-2018. Our Hematopathology database was queried to identify PB and BMA MFC sample pairs with samples considered "paired" if measured within one week of each other. If an individual had multiple pairs, all were included unless otherwise specified. Ten-color MFC was performed routinely on BMA aspirates with a panel of three antibody combinations, with the same antibody combinations applied to PB samples. When identified, the abnormal population was quantified as a percentage of the total CD45+ white cell events. Any level of residual disease was considered positive. Complete remission (CR) and relapse were defined according to the European LeukemiaNet 2017 classification. Relationship between PB and BMA blast % was measured using Spearman's Rank-Order Correlation. Relationship between PB and BMA samples identified as positive or negative is illustrated using 2 X 2 tables (Table 1). RESULTS: Considering all 724 sample pairs, the Spearman correlation coefficient between PB and BMA blast percentage was 0.93, and was 0.91 considering only the first sample pair for each individual patient (n= 482). 315 sample pairs were positive by PB, 97% of which were also positive by BMA while 95% of 409 pairs negative by PB were also negative by BMA. Similar results were seen considering only a patient's first pair. Restricting analysis to patients with pairs obtained between the dates of CR and relapse, the Spearman correlation coefficient was 0.82 with 91% of 35 cases positive in PB also positive in BMA; 93% of 114 pairs negative in PB were also negative in marrow. As a complementary means to compare pairs when AML burden was low, we examined only pairs where the BMA MFC showed <5% blasts. Here, the Spearman correlation coefficient between PB and BMA blasts was 0.83. 90% of 70 positive PB cases were also positive by BMA while 95% of 295 negative PB cases were also negative by BMA. Examining pairs taken from patients in morphologic remission immediately prior to undergoing hematopoietic cell transplant yielded a Spearman correlation coefficient of 0.92, with all 9 PB positive cases also being positive in BMA and 96% of PB negative cases being negative in BMA. CONCLUSIONS: This is the largest cohort of AML PB and BMA sample pairs analyzed by MFC to-date. The percentages of blasts measured in PB and BMA are strongly correlated. In the 365 pairs from patients with MRD-level disease, the predictive value of PB MFC positivity for BMA positivity was 90% (63/70) while the predictive value PB MFC negativity for BMA negativity was 95%. Disclosures Othus: Glycomimetics: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Gardner:Abbvie: Speakers Bureau. Walter:BioLineRx: Consultancy; BiVictriX: Consultancy; Boehringer Ingelheim: Consultancy; Boston Biomedical: Consultancy; Covagen: Consultancy; Daiichi Sankyo: Consultancy; Kite Pharma: Consultancy; New Link Genetics: Consultancy; Pfizer: Consultancy, Research Funding; Race Oncology: Consultancy; Seattle Genetics: Research Funding; Argenx BVBA: Consultancy; Aptevo Therapeutics: Consultancy, Research Funding; Jazz Pharmaceuticals: Consultancy; Astellas: Consultancy; Agios: Consultancy; Amgen: Consultancy; Amphivena Therapeutics: Consultancy, Equity Ownership.

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Dissecting Signaling Network Responses to PAK4 Allosteric Modulators (PAMs) in Cell Subsets within Primary Human Acute Myeloid Leukemia Samples

Blood ◽

10.1182/blood.v126.23.3686.3686 ◽

2015 ◽

Vol 126 (23) ◽

pp. 3686-3686

Author(s):

Paul Brent Ferrell ◽

William Senapedis ◽

Alexander Cook ◽

Erkan Baloglu ◽

Yosef Landesman ◽

...

Keyword(s):

Bone Marrow ◽

Flow Cytometry ◽

Board Of Directors ◽

Cell Lines ◽

Myeloid Leukemia ◽

Research Funding ◽

Leukemia Stem Cells ◽

Allosteric Modulators ◽

Advisory Committees ◽

Acute Myeloid

Abstract Background: Acute myeloid leukemia (AML) is the most common acute leukemia in adults and has a poor outcome with limited treatment options in patients with relapsed or resistant disease. Therapy resistance in AML is likely related to the inadequacy of therapy within leukemia cell subsets, including leukemia stem cells (LSCs). The p21-activated kinase (PAK) family of proteins was shown to be overexpressed in cancer cells and to play a key role in proliferation, survival, and maintenance of cellular structure. The series of orally bioavailable PAK4 allosteric modulators (PAM) have previously been shown to have activity in hematological cancer cell lines, including those derived from acute myeloid leukemia (AML) (Senapedis et al. Blood124, 2208-2208). Understanding how therapies target cellular subsets within primary patient samples could aid drug development by revealing any subset specific drug effects. In this project, we studied the effects of p21-activated kinase 4 (PAK4) modulation in AML samples. PAK4 modulation has been shown to have significant effects on many intracellular signaling pathways, including PI3K/AKT, MAPK/ERK and WNT/β-catenin pathways (Senapedis et al. Blood124, 2208-2208). It is unknown whether PAMs will have similar activity in primary leukemia cells. Likewise, it is currently unclear to what extent PAMs will differentially impact primary cell subsets including leukemia stem cells and non-malignant cell subsets that may be critical to recovery of bone marrow functions. We have previously shown that the single cell biology platform of flow cytometry is well-suited for dissecting clinically relevant signaling network mechanisms in primary human AML (Irish et al. Cell, 118(2):217-28). Methods: Flow cytometry was used to dissect the impact of an orally bioavailable PAM in AML cell lines and primary patient tissue. Cell lines chosen for this study included NRAS mutant KG-1 and Kasumi-1, which carry t(8;21) and express the AML1:ETO fusion protein. Primary AML biopsies were acquired from bone marrow or blood prior to any treatment and patients were identified and consented for this study according to a local Institutional Review Board-approved protocol. AML tissue samples were viably cryopreserved and then assayed ex vivo. Established protocols were used for phospho-specific flow cytometry, fluorescent cell barcoding, and data analysis in Cytobank (Irish et al. Cell, 118(2):217-28, Doxie and Irish, Curr Top Microbiol Immunol. 377:1-21). Results: Differential effects of PAK4 inhibition were observed between cell lines and among cell subsets from AML patient bone marrow. In leukemia cell lines and patient samples, p-ERK and p-S6 showed marked inhibition via PAM, though degree of inhibition varied. In AML patient samples, PAMs blocked signaling responses in p-ERK specifically in AML blasts, but spared normal CD45hi mononuclear cells (0.88 vs. 0.29-fold reduction (arcsinh scale) in p-ERK at 10 nM). Within the AML blast population, CD34+ CD38- and CD34+ CD38+ AML subsets showed similar PAM dose response via p-ERK. Conclusions: Single cell analysis effectively distinguishes effects of PAK4 inhibition via a series of allosteric modulators of PAK4 (PAMs) on leukemia and non-leukemia subsets in the same sample. PAM reduced immediate p-ERK and p-S6 levels in primary leukemia and cell lines. Notably, inhibition in various subsets within human AML was successfully measured by phospho-flow cytometry. Signaling changes in p-ERK were minimal within non-leukemic mature CD45+ mononuclear cells found in primary patient biopsies. Analysis of CD34+ CD38- cells indicates that PAMs could have activity within leukemia stem cells, and, at least, effect the AML progenitors. These findings support further investigation into the mechanism of action and treatment potential of PAMs in AML. Disclosures Senapedis: Karyopharm Therapeutics, Inc.: Employment, Patents & Royalties. Baloglu:Karyopharm Therapeutics Inc.: Employment, Equity Ownership. Landesman:Karyopharm: Employment. Irish:Novartis: Honoraria; Cytobank, Inc.: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Karyopharm: Research Funding; InCyte: Research Funding. Savona:Gilead: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Incyte: Membership on an entity's Board of Directors or advisory committees, Research Funding; Karyopharm: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding.

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Acute Myeloid Leukemia Expands Osteoprogenitor Rich Niche in the Bone Marrow but Resorbs Mature Bone Causing Osteopenia/Osteoporosis in Animal Models

Blood ◽

10.1182/blood-2018-99-117258 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 86-86 ◽

Cited By ~ 1

Author(s):

Bin Yuan ◽

Stanley Ly ◽

Khoa Nguyen ◽

Vivien Tran ◽

Kiersten Maldonado ◽

...

Keyword(s):

Bone Marrow ◽

Board Of Directors ◽

Myeloid Leukemia ◽

Research Funding ◽

Bone Surface ◽

Advisory Committees ◽

Osteoprogenitor Cells ◽

Equity Ownership ◽

Acute Myeloid ◽

Mature Bone

Abstract Acute myeloid leukemia (AML) is one of the most aggressive hematological malignancy that originates in the bone marrow (BM). Despite advances in the molecular characterization of AML, factors regulating its progression are still not known. Among several BM niches that support AML growth in the BM, the osteogenic niche has gained attention in recent years owing to its potential role in leukemogenesis. Genetic alterations in osteoprogenitor cells have been shown to induce myeloid leukemia in mouse models. We reported recently that AML cells induce osteogenic differentiation in mesenchymal stromal cells (MSCs) in the BM to facilitate faster AML engraftment in mice (Battula et al., JCI Insight, 2017). However specifics of this osteogenic niche generated by AML are not known. Here we hypothesize that AML expands osteo-progenitor rich niche in the BM, but that the mature bone is reduced. To determine the type of AML-induced osteo-lineage differentiation in the BM, we generated transgenic reporter mice by crossing Osx-CreERt2 mice with Ocn-GFP; ROSA-tdTomato mice. The resulting triple transgenic mice has the genotype of Osx-CreERt2;Ocn-GFP;ROSA-tdTomato. In these mice the tdTomato (red) positive cells represents osteo-lineage cells that originate from Osterix expressing (Osx+) cells, whereas a GFP+ cell represents an osteocalcin-expressing (Ocn+) mature osteoblast. Seven day old triple transgenic mice were injected with tamoxifen to activate Osx-CreERT2 to mark the Osx+ cells with tomato reporter. To investigate the osteogenic cell type that is induced by AML cells in the bone marrow, we implanted murine AML cells with MLL-ENL fusion proteins into Osx-CreERt2;Ocn-GFP;ROSA-tdTomato mice. Three weeks after implantation of AML cells, the femurs and tibia of these mice were dissected and subjected to histological evaluation using fluorescence microscopy. In control BM without AML, the GFP+ (Ocn+) cells were found in the trabecular bone surface as well as the periosteum of the bone, whereas the tdTomato+ (Osx+)cells were found in the marrow and the bone matrix; this suggests that some of the osteocytes originated from tamoxifen-induced Osx+ osteoprogenitor cells. Interestigly, in mice implanted with AML cells, we found a 3-4 fold increase in Osx+ cells in the marrow compared to normal BM (Fig 1A). However, the number of GFP+ cells on the endosteum and trabecular bone surface was reduced, suggesting that AML cells might expand osteoprogenitor cells but not fully differentiated mature osteoblasts. Next, to investigate whether AML cells affect the mature bone, AML PDX cells developed in our laboratory were implanted into NSG mice. The PDX models usually take 12-14 weeks to achieve >90% engraftment in the peripheral blood which provides ample time to observe alterations in bone composition. At this stage, the mice were subjected to computed tomography imaging to measure bone architecture, volume (BV), mineral density (BMD) and bone volume fraction (BVF). Interestingly, we observed large bone cavities close to epiphysis and metaphysis areas in the femur and tibia of mice with AML (Fig 1B). In addtion, BMD and BVF in these mice were reduced by 20-30% compared to control mice without leukemia. To validate the bone resorption in these mice, bone histomorphometric analysis was performed on femurs and tibias from mice with and without AML. Masson-Goldner's Trichrome staining revealed a 5- to 10-fold decrease in the trabecular and cortical bone thickness in AML femurs compared to normal femurs. Moreover, measurements of osteoclast activation by tartrate-resistant acidic phosphatase (TRAP) revealed positive staining for osteoclasts on the endosteal surface and massive bone resorption in AML bone compared to normal bone. Mechanistic studies showed that AML cells inhibit osteoprotegerin (OPG) ~10 fold in MSCs, a factor that inhibits the RNAK ligand which in turn activates osteoclasts that breakdown the bone. In conclusion, our data suggest that bone homeostasis is dysregulated in AML by induction of osteogenic and osteolytic activities simultaneously. AML cells induce an osteoprogenitor niche but also activate osteoclasts resulting in osteopenia/osteoporosis in mouse models. In-depth analysis of bone remodeling in AML patients could result in new insights into the pathobiology of the disease and provide therapeutic avenues for AML. Disclosures Andreeff: Amgen: Consultancy, Research Funding; Oncolyze: Equity Ownership; United Therapeutics: Patents & Royalties: GD2 inhibition in breast cancer ; Daiichi-Sankyo: Consultancy, Patents & Royalties: MDM2 inhibitor activity patent, Research Funding; Celgene: Consultancy; Astra Zeneca: Research Funding; Jazz Pharma: Consultancy; Oncoceutics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; SentiBio: Equity Ownership; Eutropics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Aptose: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Reata: Equity Ownership. Battula:United Therapeutics Inc.: Patents & Royalties, Research Funding.

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Dose Escalation Study of BET Inhibitor PLX2853 in Patients with Relapsed or Refractory Acute Myeloid Leukemia or High Risk Myelodysplastic Syndrome

Blood ◽

10.1182/blood-2019-127497 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 1391-1391 ◽

Cited By ~ 1

Author(s):

Naveen Pemmaraju ◽

Uma Borate ◽

Melhem Solh ◽

Gautam M. Borthakur ◽

Amy E. DeZern ◽

...

Keyword(s):

High Risk ◽

Board Of Directors ◽

Myeloid Leukemia ◽

Research Funding ◽

Plasma Concentrations ◽

Target Engagement ◽

Advisory Committees ◽

Refractory Acute Myeloid Leukemia ◽

Acute Myeloid ◽

Refractory Aml

Background: PLX2853 is an orally available, non-benzodiazepine BET (bromodomain and extraterminal domain) inhibitor that exhibits low nanomolar potency and a modest preference for binding to the second bromodomain (BD2) of the BET proteins. By regulating genes (e.g. MYC and BCL2) critical to leukemic cell growth and survival, PLX2853 demonstrated broad anti-leukemic activity both as a single agent and in combination with other therapeutic agents in preclinical models. The pharmacokinetic (PK) profile in solid tumor patients revealed a short half-life (< 3 hour) enabling high peak plasma concentrations and nearly complete elimination from the plasma 9 hour post dose. Since strong and prolonged suppression of BET proteins have often untoward effects in normal tissues, the PLX2853 PK profile is hypothesized to be associated with improved tolerability by allowing transient target engagement followed by time for recovery after daily dosing. Methods: We are conducting an open-label, Phase 1b (Ph1b) study of PLX2853 as a single oral agent administered daily in adult patients with relapsed or refractory acute myeloid leukemia (AML) or high risk myelodysplastic syndrome (MDS) using a modified continuous reassessment model (mCRM) with escalation with overdose control (EWOC) to determine the recommended phase 2 dose (RP2D). Up to 36 patients are expected to enroll. The dosing cycle and dose limiting toxicity window (DLT) is 21 days. Primary objectives include safety and PK. Secondary objectives include measures of preliminary efficacy, and exploratory objectives include pharmacodynamics (PD) biomarker assessments in various tissues. Enrollment through Cohort 2 (40 mg QD) is ongoing as of July 2019. Results: Five subjects with relapsed or refractory AML (median age 65 years) have received PLX2853 in escalating doses from 20 to 40 mg QD. Among these first 5 patients treated, the most common treatment emergent adverse events (AEs) regardless of causality in > 1 patient: decreased appetite (n=3), nausea (n=2), diarrhea (n=2), peripheral edema (n=2), cough (n=2), oropharyngeal pain (n=2), blood bilirubin increase (n=2), anemia (n=2), febrile neutropenia (n=2), fatigue (n=2), bacteremia (n=2), headache (n=2), dyspnea (n=2), and hypertension (n=2). Most were grade (G) 1-2. Treatment emergent AEs > G2 in > 1 patient included: anemia (n=2), febrile neutropenia (n=2) and hypertension (n=2). No treatment-related serious AEs or DLTs have been observed. Following a 20 mg daily dose of PLX2853, median time to reach maximal plasma concentrations (Tmax) is 1 hour and the absorption half-life (T1/2) is < 3 hours. Conclusions: In an ongoing Ph1b study, PLX2853 has now completed its first dosing cohort for patients with relapsed or refractory AML or high risk MDS, and no DLT has been observed yet. As dose escalation continues, PK, PD, preliminary safety and efficacy data will be assessed further to determine the clinical significance of target engagement. This clinical trial is registered at clinicaltrials.gov: NCT03787498. Disclosures Pemmaraju: mustangbio: Consultancy, Research Funding; abbvie: Consultancy, Honoraria, Research Funding; samus: Research Funding; celgene: Consultancy, Honoraria; cellectis: Research Funding; Stemline Therapeutics: Consultancy, Honoraria, Research Funding; novartis: Consultancy, Research Funding; plexxikon: Research Funding; Daiichi-Sankyo: Research Funding; sagerstrong: Research Funding; affymetrix: Research Funding; incyte: Consultancy, Research Funding. Borate:Novartis: Consultancy; Takeda: Consultancy; Pfizer: Consultancy; Daiichi Sankyo: Consultancy; AbbVie: Consultancy. Solh:ADC Therapeutics: Research Funding; Amgen: Speakers Bureau; Celgene: Speakers Bureau. Borthakur:Polaris: Research Funding; Arvinas: Research Funding; Agensys: Research Funding; Tetralogic Pharmaceuticals: Research Funding; Cantargia AB: Research Funding; Argenx: Membership on an entity's Board of Directors or advisory committees; BioLine Rx: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Oncoceutics, Inc.: Research Funding; Eli Lilly and Co.: Research Funding; BMS: Research Funding; AstraZeneca: Research Funding; Bayer Healthcare AG: Research Funding; Novartis: Research Funding; FTC Therapeutics: Membership on an entity's Board of Directors or advisory committees; AbbVie: Research Funding; Strategia Therapeutics: Research Funding; Cyclacel: Research Funding; Xbiotech USA: Research Funding; Eisai: Research Funding; Merck: Research Funding; BioTheryX: Membership on an entity's Board of Directors or advisory committees; Oncoceutics: Research Funding; NKarta: Consultancy; Incyte: Research Funding; Janssen: Research Funding; GSK: Research Funding; PTC Therapeutics: Consultancy. DeZern:Astex Pharmaceuticals, Inc.: Consultancy; Celgene: Consultancy. Zhang:Plexxikon Inc.: Employment. Powell:Plexxikon Inc.: Employment. Severson:Plexxikon Inc.: Employment. Inokuchi:Plexxikon Inc.: Employment. Matusow:Plexxikon Inc.: Employment. Halladay:Plexxikon Inc.: Employment. Hsu:Daiichi Sankyo, Inc.: Employment. Watkins:Plexxikon Inc.: Employment. Walling:Myovant Sciences: Consultancy; Nurix: Consultancy; Aduro Biotech: Consultancy; Plexxikon: Consultancy; CytomyX: Consultancy; Flag Therapeutics: Consultancy; Aminex: Consultancy; Immunext: Consultancy; SensenBio: Consultancy; Harpoon Therapeutics: Consultancy. Tsiatis:Plexxikon Inc.: Employment. Mims:PTC Therapeutics: Membership on an entity's Board of Directors or advisory committees; Astellas Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Agios Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees.

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Azacitidine in Patients with Acute Myeloid Leukemia: Impact of Intermediate-Risk Vs High-Risk Cytogenetics on Patient Outcomes

Blood ◽

10.1182/blood.v124.21.955.955 ◽

2014 ◽

Vol 124 (21) ◽

pp. 955-955 ◽

Cited By ~ 1

Author(s):

Lisa Pleyer ◽

Sonja Burgstaller ◽

Reinhard Stauder ◽

Michael Girschikofsky ◽

Werner Linkesch ◽

...

Keyword(s):

Bone Marrow ◽

High Risk ◽

Board Of Directors ◽

Myeloid Leukemia ◽

Research Funding ◽

Negative Impact ◽

Intermediate Risk ◽

Advisory Committees ◽

Bone Marrow Blasts ◽

Acute Myeloid

Abstract Background Several studies, including retrospective analyses of patient registries1,2 and a subanalysis of the phase III MDS-AZA-001 trial3 suggest that poor-risk cytogenetics negatively impact overall survival (OS) in patients with myelodysplastic syndrome (MDS) and World Health Organization (WHO)-defined acute myeloid leukemia (AML) treated with azacitidine (AZA). There are few data available to indicate whether AZA has improved clinical activity vs conventional care in AML patients with adverse cytogenetics. However, in a subanalysis of MDS-AZA-001 (MDS and AML [20–30% bone marrow blasts]) patients with –7/–7q abnormalities had better OS with AZA than low-dose cytarabine (21.4 vs 3.5 months, respectively) supporting significant activity of AZA in patients with adverse cytogenetics.4 Methods In this retrospective study of the Austrian AZA Registry (N=346), we compared patients with WHO-AML and intermediate- (n=228) vs high-risk (n=74) cytogenetics according to Medical Research Council (MRC) criteria. Outcomes were also assessed with respect to AZA treatment line. Results The intermediate-risk cytogenetics group comprised 228 patients (AZA 1st line, n=109; AZA ≥2nd line, n=119), and the high-risk cytogenetics group comprised 74 patients (AZA 1st line, n=39; AZA ≥2nd line, n=35; Figure 1). Comparison of baseline characteristics of both groups revealed significant differences with regard to prevalence of males and Eastern Cooperative Oncology Group Performance Status (ECOG PS) >2 for patients with high-risk cytogenetics receiving AZA 1st line, but not in those receiving AZA ≥2nd line. Peripheral blood blasts were present in a significantly larger proportion of high- than intermediate-risk patients (Figure 1). In patients who received AZA 1st line, median number of AZA cycles was 6 for both the intermediate- and high-risk cytogenetic groups (range: 1–46 and 1–25, respectively). Median time from diagnosis to AZA start was <1 month for AZA 1st line and >7.6 months for AZA ≥2nd line. Median time from AZA stop to death was <2 months in all cohorts. In the whole cohort, the overall response rate (ORR) according to International Working Group (IWG) 2003 criteria5 was similar for patients with intermediate- and high-risk cytogenetics (complete response [CR] + CR with incomplete blood count recovery [CRi] + partial response [PR]: 32.0 vs 20.3%; p=0.106; Figure 1). Rates of hematologic improvement (HI) according to IWG 2006 criteria6 were also not significantly different (54.4 vs 75.6; p=0.063), and when ORR and HI were combined, the difference remained non-significant (47.4 vs 46.0%; p=0.885; Figure 1). Median OS was consistently higher in patients with intermediate- than high-risk cytogenetics (9.8 vs 5.4 months for the total cohort; p=0.046 [Figures 1 and 2a]; 13.5 vs 9.5 months for AZA 1st line [not significant]; and 7.6 vs 3.5 months for AZA ≥2nd line; p=0.005 [Figure 1]). However, median OS for responding patients (CR/CRi/PR/HI) was similar for patients with intermediate- and high-risk cytogenetics, irrespective of treatment line (19.9 vs 19.3 months for all responders; 20.5 vs 21.7 months for AZA 1st line; and 18.5 vs 15.0 months for AZA ≥2nd line). Furthermore, presence of a monosomal karyotype had a significant negative impact on OS (Figure 2b). None of the baseline factors analyzed had an impact on OS in patient subgroups with intermediate- or high-risk cytogenetics, except number of comorbidities >3. Conclusions Here, we compared outcomes of 302 WHO-AML patients with intermediate- vs high-risk cytogenetics treated with AZA. In line with recent data of MDS patients,1 baseline cytogenetics did not seem to have a significant effect on response to AZA. However, in agreement with other studies of AZA in MDS/WHO-AML patients,1–3 high-risk cytogenetics had a negative impact on survival compared with intermediate-risk cytogenetics in WHO-AML treated with AZA. 1. Sebert M, et al. Oral presentation at ASH 2013. Abstract 389 2. Thepot S, et al. Am J Hematol 2014;89:410–6 3. Fenaux P, et al. J Clin Oncol 2010;28:562–9 4. Fenaux P, et al. Br J Haematol 2010;149:244–9 5. Cheson BD, et al. J Clin Oncol 2003;21:4642–9 6. Cheson BD, et al. Blood 2006;108:419–25 Figure 1 Figure 1. Figure 2 Figure 2. Disclosures Pleyer: AOP Orphan Pharmaceuticals: Honoraria; Novartis: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria; Celgene: Consultancy, Honoraria. Off Label Use: Vidaza (azacitidine) is indicated for the treatment of adult AML patients who are not eligible for haematopoietic stem cell transplantation with 20–30 % blasts and multi-lineage dysplasia, according to WHO classification. This cohort also includes AML-patients with >30% bone marrow blasts.. Burgstaller:AOP Orphan Pharmaceuticals: Honoraria; Novartis: Honoraria; Mundipharma: Honoraria; Celgene: Consultancy. Stauder:Novartis: Research Funding; Ratiopharm: Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding. Girschikofsky:Pfizer: Honoraria, Research Funding; Mundipharm: Consultancy, Honoraria. Pfeilstöcker:Janssen-Cilag: Honoraria; Novartis: Consultancy, Honoraria; Celgene: Consultancy, Honoraria. Lang:Celgene: Consultancy. Sperr:Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria; Phadia: Research Funding. Valent:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Greil:Sanofi Aventis: Honoraria; Roche: Honoraria; Pfizer: Honoraria, Research Funding; Boehringer-Ingelheim: Honoraria; Astra-Zeneca: Honoraria; Novartis: Honoraria; Genentech: Honoraria, Research Funding; Janssen-Cilag: Honoraria; Merck: Honoraria; Mundipharma: Honoraria, Research Funding; Eisai: Honoraria; Amgen: Honoraria, Research Funding; Celgene: Consultancy, Research Funding; Cephalon: Consultancy, Honoraria, Research Funding; Bristol-Myers-Squibb: Consultancy, Honoraria; GSK: Research Funding; Ratiopharm: Research Funding.

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