ERK1/2 Inhibition Overcomes Resistance in Acute Myeloid Leukemia (AML) and Alters Mitochondrial Dynamics

Abstract Background: Presence at diagnosis or acquisition of activating RAS pathway mutations is a pervasive mechanism of resistance to therapy in AML. Efforts to directly target mutant RAS have been unsuccessful and the efficacy of BRAF and MEK inhibitors has been limited due to compensatory reactivation of MAPK signaling. ERK1/2 (ERK) is a key downstream component in the MAPK pathway and therefore represents an attractive target for inhibiting MAPK signaling. Compound 27 (1) is a dual-mechanism inhibitor of ERK that inhibits both the catalytic activity of ERK and its phosphorylation by MEK. It is a close analog of ASTX029, a dual-mechanism ERK inhibitor currently under clinical investigation in solid tumors (NCT03520075). Objectives: We analysed the preclinical activity of Compound 27 in AML, investigated its mechanism of action and ability to overcome resistance. Results: Using a panel of 9 AML cell lines, the IC50 value for single agent Compound 27 was in the low to intermediate nanomolar range (1.89-388 nM). Decreased ERK phosphorylation was confirmed by Western blot analysis. To better characterize the biological effects of Compound 27, we performed mass cytometry (CyTOF) analysis of NRAS-mutated OCI-AML3 cells. This experiment showed approximately 75% downregulation of CyclinB1 and cMyc in 250 nM drug-treated cells versus untreated cells (Figure 1a). The expression of anti-apoptotic proteins, including MCL1, BclXL and Bcl2, were also decreased. Western blot analysis confirmed increased cleaved PARP, and reduced cMyc and cell cycle-related proteins CyclinB1, CyclinD1 and CDK4 with Compound 27 treatment. In isogenic cells, p53 knock-down had no effect on the efficacy of Compound 27. We next investigated the efficacy of simultaneous inhibition of ERK and Bcl-2 in AML cells. Compound 27 sensitized OCI-AML3 cells, which are intrinsically resistant to ABT-199 (a Bcl-2 inhibitor), to treatment with ABT-199 and shifted the cytostatic effect of the single agents to a cytotoxic effect with a combination index (CI) of 0.008 (cell death 91% for combination versus 20% with ABT-199 alone). This suggests strong synergistic effects of combination treatment (Figure 1b). In OCI-AML2 cells with acquired resistance to ABT-199, the combination increased apoptosis to 80% as compared to 20% with ABT-199 alone. Compound 27 sensitized bulk CD45+ as well as CD34+CD38-leukemia progenitor cells to ABT-199. Compound 27 also sensitized FLT3-ITD mutant human AML cell lines MOLM13, MOLM14, MV-4-11 and murine Ba/F3-ITD cells to the FLT3 inhibitor AC220 (CI in MOLM13=0.3). Synergy of Compound 27 and 5-azacitidine was also observed (p=0.009). Leukemia microenvironment-mediated resistance to therapy is partly mediated by MAPK activation. We co-cultured OCI-AML3 and MOLM13 cells with normal bone marrow-derived mesenchymal stromal cells (NMSCs) to mimic the bone marrow microenvironment and analysed the effect of Compound 27 in combination with either ABT-199 or AC220. Combination drug treatment were more effective in terms of cytoreduction and apoptosis induction in coculture. However, neither combination was able to completely overcome stroma-mediated resistance (Figure 1b). Analysis of other stroma-relevant molecules in coculture showed that CXCR4 was increased while CD44 was decreased in response to ERK inhibition. Effective reactive oxygen species (ROS) mitigation and hyper-active mitochondrial fission is important for maintaining "stemness" of AML cells (2). ERK phosphorylates DRP1, which is necessary for mitochondrial fission. Treatment of OCI-AML3 cells with Compound 27 led to increased mitochondrial ROS, decreased levels of pDRP1(Ser616) and increased mitochondrial length, suggesting impaired fission and reduced "stemness" of AML cells (Figure 1c). Conclusion: ERK inhibition by Compound 27 synergizes with 5-azacitidine, ABT-199 and AC220 and can overcome primary or acquired resistance. The impact on mitochondrial dynamics suggests a potential impact on leukemia stem cells. Additional mechanistic confirmatory work is in progress. References: 1. Heightman TD, Berdini V, Braithwaite H, et al. Fragment-based discovery of a potent, orally bioavailable inhibitor that modulates the phosphorylation and catalytic activity of ERK1/2. J Med Chem. 2018;61(11):4978-4992. 2. Schimmer AD. Mitochondrial Shapeshifting Impacts AML Stemness and Differentiation. Cell Stem Cell. 2018;23(1):3-4. Figure 1 Figure 1. Disclosures Hindley: Astex Pharmaceuticals: Current Employment. Dao: Astex Pharmaceuticals, Inc.: Current Employment. Sims: Astex Pharmaceuticals: Current Employment. Andreeff: Medicxi: Consultancy; Syndax: Consultancy; Aptose: Consultancy; ONO Pharmaceuticals: Research Funding; AstraZeneca: Research Funding; Amgen: Research Funding; Reata, Aptose, Eutropics, SentiBio; Chimerix, Oncolyze: Current holder of individual stocks in a privately-held company; Breast Cancer Research Foundation: Research Funding; Karyopharm: Research Funding; Glycomimetics: Consultancy; Senti-Bio: Consultancy; Oxford Biomedica UK: Research Funding; Daiichi-Sankyo: Consultancy, Research Funding; Novartis, Cancer UK; Leukemia & Lymphoma Society (LLS), German Research Council; NCI-RDCRN (Rare Disease Clin Network), CLL Foundation; Novartis: Membership on an entity's Board of Directors or advisory committees. Borthakur: University of Texas MD Anderson Cancer Center: Current Employment; Takeda: Membership on an entity's Board of Directors or advisory committees; Astex: Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Ryvu: Research Funding; ArgenX: Membership on an entity's Board of Directors or advisory committees; Protagonist: Consultancy; GSK: Consultancy.

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Activating KRAS, NRAS, and BRAF Mutants Enhance Proteasome Capacity and Reduce Endoplasmic Reticulum Stress in Multiple Myeloma, Thereby Promoting Plasma Cell Survival and Proteasome Inhibitor Resistance

Blood ◽

10.1182/blood-2018-99-117577 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 406-406

Author(s):

Fazal Shirazi ◽

Richard J. Jones ◽

Isere Kuiatse ◽

Zuzana Berkova ◽

Hua Wang ◽

...

Keyword(s):

Multiple Myeloma ◽

Transcription Factor ◽

Board Of Directors ◽

Cell Lines ◽

Proteasome Inhibitor ◽

Research Funding ◽

Mek Inhibitor ◽

Mapk Signaling ◽

Dominant Negative ◽

Advisory Committees

Abstract Introduction: Multiple myeloma, a malignant proliferation of differentiated plasma cells, is the second most commonly diagnosed hematologic malignancy, and the number of cases may grow by almost 60% between 2010 and 2030. Recent therapeutic advances, including the use of proteasome inhibitors (PIs), have contributed to a doubling of the median overall survival in myeloma patients. This has been paralleled by an increased understanding of the mutational spectrum in this disease, which was first noted almost three decades ago to harbor KRAS and NRAS mutations. KRAS, NRAS, and BRAF mutations which induce p44/42 Mitogen-activated protein kinase (MAPK) signaling are found in about half of myeloma patients, and seem to contribute to proteasome inhibitor (PI) resistance, but the underlying mechanisms still remains elusive. Methods: ANBL-6 and U266 human-derived myeloma cell lines have endogenous wild-type (WT) KRAS, NRAS, and BRAF, and were used in this study. All cell lines were validated through The MD Anderson Cancer Center Characterized Cell Line Core Facility. We established lines stably expressing WT, constitutively active (CA)(G12V/G13D/Q61H), or dominant negative (DN)(S17N) KRAS and NRAS mutants, or V600E or DN BRAF. Cell viability was evaluated using the WST-1 tetrazolium reagent, while the chymotrypsin-, trypsin- and caspase-like activities were determined using fluorogenic substrates. Results: CA KRAS, NRAS, and BRAF mutants reduced the sensitivity of ANBL-6 and U266 cells to bortezomib and carfilzomib, while their DN variants sensitized cells to both PIs. This was associated with an induction by these CA mutants of the proteasome chymotrypsin-, trypsin- and caspase-like activities, while the DN variants reduced proteasome activity. These activity changes occurred in parallel with increased expression at both the mRNA and protein levels of catalytically active Proteasome subunit beta (PSMB)-8, PSMB9, and PSMB10, and of the proteasome assembly chaperone Proteasome maturation protein (POMP). Mechanistic studies showed that MAPK induction by the CA mutants caused activation of the ETS transcription factor (ELK1), which was found to have consensus binding sites in the promoters of PSMB8, PSMB9, PSMB10, and POMP. Notably, ELK1 suppression reduced PSMB8, PSMB9, PSMB10, and POMP expression, directly linking RAS/RAF/MAPK signaling to proteasome biology, and this suppression enhanced PI sensitivity. Inhibition of MAPK signaling with either the MAPK kinase (MEK) inhibitor selumetinib or the pan-RAF inhibitor TAK-632 showed synergistic activity with either bortezomib or carfilzomib that was more consistent in cell lines harboring CA mutants as opposed to the DN or WT constructs. Combination regimens of selumetinib or TAK-632 with either bortezomib or carfilzomib induced greater inhibition of the proteasome chymotrypsin-, trypsin- and caspase-like activities than the PIs as single agents. Finally, CA KRAS, NRAS, and BRAF mutants reduced expression levels of genes and proteins involved in the unfolded protein response (UPR), including Activating transcription factor (ATF)-4, -5, and -6, as well as C/EBP homologous protein transcription factor (CHOP) and the spliced variant of X-box binding protein 1 (XBP1s). In contrast, their dominant negative counterparts enhanced expression of the UPR effectors, consistent with an increase in endoplasmic reticulum (ER) stress. Conclusion: Taken together, the data support the hypothesis that activating MAPK pathway mutations enhance PI resistance by increasing proteasome capacity, and provide a rationale for targeting such patients with PI/RAF or PI/MEK inhibitor combinations. Moreover, they argue that these mutations promote plasma cell survival by reducing cellular stress, thereby distancing myeloma cells from the apoptotic threshold, potentially explaining their high frequency in myeloma. Disclosures Lee: Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies Corporation: Consultancy; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Chugai Biopharmaceuticals: Consultancy; Takeda Oncology: Consultancy, Membership on an entity's Board of Directors or advisory committees; Kite Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees. Dick:Takeda Oncology: Employment, Equity Ownership. Chattopadhyay:Takeda Oncology: Employment. Orlowski:Janssen Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; Genentech: Consultancy; BioTheryX, Inc: Consultancy, Membership on an entity's Board of Directors or advisory committees; Millenium Pharmaceuticals: Consultancy, Research Funding; Bristol Myers Squibb: Consultancy; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Poseida: Research Funding; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding.

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Activation of NF-Kappa B-p62-NRF2 Signaling Supports the Survival of CLL Cells That Express High Levels of ROR1

Blood ◽

10.1182/blood-2018-99-115564 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 3122-3122

Author(s):

Elsa Sanchez-Lopez ◽

Emanuela M. Ghia ◽

Laura Antonucci ◽

Laura Z. Rassenti ◽

Yun Chen ◽

...

Keyword(s):

Mrna Expression ◽

Disease Progression ◽

Board Of Directors ◽

Research Funding ◽

Nuclear Factor ◽

High Level Expression ◽

Advisory Committees ◽

Resistance To Therapy ◽

High Level ◽

Inducible Genes

Abstract Recent studies have linked the autophagy adaptor p62/SQSTM1 to tumorigenesis via NRF2 signaling. Increased accumulation p62 is associated with disease progression in many cancers, however its expression in CLL has yet to be investigated. Importantly, p62, encoded by the SQSTM1 gene, mRNA expression and protein accumulation is regulated by nuclear factor-kappa B (NF-κB), a key transcription factor for CLL survival. In addition, CLL cells express receptor tyrosine kinase-like orphan receptor 1 (ROR1), an oncoembryonic protein that also is expressed on cancer cells of numerous malignancies, including those reported to show accumulation of p62. As in solid-tumor malignancies, high-level expression ROR1 in CLL is associated with enhanced disease-progression and shorter overall survival (Cui B, et al, Blood 25:2931, 2016). Furthermore, recent studies found that activation of Wnt5a-ROR1 cascade induces NF-κB activation and increased expression of NF-κB target genes in CLL (Chen, Y et al, submitted ASH Abstract, 2018). Additionally, CLL cells exhibit increased basal activation of nuclear factor erythroid 2-related factor 2 (NRF2), which supports antioxidant and detoxifying responses that enhance resistance to cytotoxic drugs. We hypothesized that high-level expression of ROR1 in CLL may influence the accumulation of p62, which in turn could lead to activation of NRF2-signaling to enhance CLL-cell survival and resistance to therapy. We found that CLL cells with high-level surface expression of ROR1 (ROR1HIGH) had significantly greater accumulation of p62 than ROR1LOW CLL cells (p=0.003). Elevated p62 accumulation was accompanied by enhanced protein and mRNA expression of NRF2 targets, including NQO1 (p=0.009), GPX2 (p=0.019), GSTM1 (p=0.001), SOD1 (p=0.001) and MDM2 (p=0.001) (n=6 ROR1LOW and n=13 ROR1HIGH). We analyzed published gene expression data (GSE13204, Kohlmann A, et al BJH 142:802, 2008), of 448 CLL cases. We designated CLL cells with expression levels of ROR1 above the medium (n=224) as ROR1HI and cases with ROR1 expression below the medium value as ROR1LO (n=224), We confirmed that SQSTM1 (p=0.01), NQO1 (p=0.0001) and HMOX1 (p=0.002) were significantly overexpressed in ROR1HI CLL patients. In addition, we segregated GSE13204 dataset into two groups: ROR1>90% (n=45), representing the 10% of patients who had CLL cells with highest levels of ROR1 mRNA, and ROR1<10% (n=45), representing the 10% of patients who had CLL cells with lowest levels of ROR1 mRNA. Consistently, SQSTM1 (p=0.009), NQO1 (p=0.02) and HMOX1 (p=0.008) were significantly overexpressed in ROR1>90%. We performed gene set enrichment analysis (GSEA) to investigate whether NRF2 inducible genes (Malhotra D, et al, Nucleic Acids Research 38(17):5718, 2010) were expressed at higher levels in ROR1HI or ROR1>90% compared with ROR1LO or ROR1<10% CLL. In both comparisons, the GSEA revealed that NRF2 inducible genes were enriched in CLL cells with high ROR1 mRNA (FDR q of 0.01 and 0.06, respectively). Collectively, these data indicate that p62-NRF2 cascade is upregulated in CLL cells with high expression of ROR1 and suggest that it may play a role in the enhanced proliferation observed in ROR1HIGH CLL cells. Similarly, ROR1HIGH CLL cells and MEC1-ROR1 CLL cell line that express high protein level of NQO1 were resistant to ABT-199 (p<0.05 and p<0.001 respectively). Such agent induces the accumulation of reactive oxygen species (ROS), which are detoxified by products of the NRF2-activated antioxidant response. The role of NQO1 in protection from cell death was confirmed using a specific pro-drug, designated as 29h, which becomes active after being metabolized by NQO1 (p<0.05). Furthermore, treatment with 29h overcame NQO1-mediated resistance to ABT-199 (venetoclax) (p<0.05), resulting in PARP cleavage and accumulation of cytoplasmic cytochrome C, markers of apoptosis. This study illustrates a previously unknown and intricate signaling network through which ROR1-NF-κB-p62-NRF2 cascade may enhance disease progression and resistance to therapy in CLL B cells that express high levels of ROR1. Disclosures Kipps: Genentech Inc: Consultancy, Research Funding; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; F. Hoffmann-La Roche Ltd: Consultancy, Research Funding; Pharmacyclics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Verastem: Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy; Verastem: Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy, Honoraria, Research Funding; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees.

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Functional Analysis of the CML Blast Crisis Transcriptome and Epigenome Using Crispr-CAS9 and Pharmacologic Approaches

Blood ◽

10.1182/blood.v126.23.2764.2764 ◽

2015 ◽

Vol 126 (23) ◽

pp. 2764-2764

Author(s):

Tun Kiat Ko ◽

Xin Xuan Sheila Soh ◽

Willie Yu ◽

Peter S. Winter ◽

Thushangi Pathiraja ◽

...

Keyword(s):

Board Of Directors ◽

Research Funding ◽

Blast Crisis ◽

Genetic Alterations ◽

Mapk Signaling ◽

Rational Approach ◽

Structural Variations ◽

Advisory Committees ◽

Paired Samples

Abstract Current models of CML blast crisis (BC) propose that expression of BCR-ABL results in genomic instability and the acquisition of genetic alterations that affect cell proliferation and survival, self-renewal and differentiation. To characterize the molecular events that underlie progression, we performed whole genome sequencing of paired samples of the same patient at CP and at BC (n = 12), as well as expression and methylation arrays of these samples and a larger validation cohort of unpaired CD34-selected samples (n = 38). Contrary to expectations, we found that the CML BC genome is relatively quiescent with regards to SNVs, indels and structural variations. In contrast, we observed widespread hyper-methylation in BC that was associated with distinct changes in expression and was independent of lineage/differentiation state. These findings suggest that in addition to genetic alterations, epigenomic events are likely to contribute substantively to BC progression. To understand the functional effects of the dysregulated transcriptome and epigenome in BC CML, we employed both pharmacologic and genetic methods to target candidate genes of interest identified in our earlier studies. To induce de-methylation of the BC genome, we treated primary samples with low doses of decitabine, a DNMT inhibitor. We found that decitabine impaired colony formation ability of BC CD34+ progenitors and concomitantly activated regulators of myeloid differentiation that were both hyper-methylated and down-regulated in BC CD34+ progenitors, such as MPO and KLF1. These results suggest that hyper-methylation does contribute to BC CD34+ progenitor function, and support the use of epigenetic therapies as a rational approach to targeting BC. The genetic approach we chose was a CRISPR-based in vitro pooled screen. We created a custom library targeting 200 genes, with an average of 5 sgRNAs per gene, and 50 non-targeting controls. We transduced K562 with the library and harvested samples at different time-points post-transduction/selection - Day 0, 7 and 21 - for deep sequencing. As expected, sgRNAs targeting essential genes such as MYC and MCM 2-7 were recurrently depleted in the population over time. More importantly, enriched sgRNAs targeted genes including TET2, which has been previously reported to be inactivated in myeloid malignancies, as well as novel candidates including RREB1, a transcription factor that binds to RAS-responsive elements (RREs) and may be involved in MAPK signaling. We will validate these targets by knocking them out individually and assessing their effect on the ability of CP cells to serially replate and/or engraft immune-deficient mice. Disclosures Chuah: Bristol-Myers Squibb: Honoraria; Novartis: Honoraria; Chiltern International: Honoraria. Takahashi:Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; BMS: Honoraria, Research Funding, Speakers Bureau; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Masis: Consultancy; Otsuka: Membership on an entity's Board of Directors or advisory committees; Celgene: Speakers Bureau; Sysmex: Research Funding, Speakers Bureau; Astellas: Speakers Bureau. Valent:Novartis: Consultancy, Honoraria, Research Funding; Ariad: Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria; Pfizer: Honoraria; Celgene: Honoraria.

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Marcks Marks Resistance to Proteasome Inhibitors: Exocytosis of Polyubiquitinated Proteins in Bortezomib-Resistant Leukemia Cells

Blood ◽

10.1182/blood.v126.23.3712.3712 ◽

2015 ◽

Vol 126 (23) ◽

pp. 3712-3712

Author(s):

Niels Franke ◽

Gertjan J.L. Kaspers ◽

Yehuda G Assaraf ◽

Johan Van Meerloo ◽

Denise Niewerth ◽

...

Keyword(s):

Acute Leukemia ◽

Board Of Directors ◽

Research Funding ◽

Acquired Resistance ◽

Proteasome Inhibitors ◽

Leukemia Cells ◽

Advisory Committees ◽

Resistance Level ◽

Proteolytic Stress ◽

Resistant Cells

Abstract Despite the proven efficacy of proteasome inhibitors like bortezomib (BTZ) in multiple myeloma, mantle cell lymphoma, and in an experimental setting in pediatric acute leukemia, development of drug resistance remains a primary hindrance. To further understand the molecular basis underlying this chemoresistance phenomenon, various leukemia cell line models with acquired resistance to BTZ were developed and characterized. One common characteristic was that acquisition of point mutations in PSMB5 and upregulation of the β5-subunit of the proteasome were key determinants of BTZ-resistance in vitro. However, it remains unclear how these drug resistance modalities translate to the overcoming of proteolytic stress imposed by proteasome inhibition. From this perspective, we here undertook a multi-modality (DNA, mRNA, miRNA) array-based analyses of human CCRF-CEM acute leukemia cells and two BTZ-resistant subclones [one with a low resistance level [(10-fold, CEM/BTZ7) and another subline with a high resistance level (140-fold, CEM/BTZ200)] to determine whether or not complementary mechanisms contribute to BTZ resistance. Gene expression profiling studies revealed markedly reduced proteolytic stress induction in drug resistant cells over a broad BTZ concentration range. Moreover, several genes involved in cytoskeleton regulation and vesicle migration were increased in resistant cells. Of all genes, myristoylated alanine-rich C-kinase substrate (MARCKS) was the most differentially overexpressed gene with 25- to 42-fold upregulation in CEM/BTZ7 and CEM/BTZ200 cells, respectively. These observations were corroborated at the protein level and solely included unphosphorylated MARCKS rather than phosphorylated MARCKS, which was marginally expressed in CEM/BTZ cells. Interestingly, MARCKS upregulation was also observed in other BTZ-resistant and leukemia cells (CEM and THP1) with acquired resistance to the proteasome inhibitor salinosporamide A and the immunoproteasome inhibitor PR924. Given the overexpression of MARCKS in proteasome inhibitor-resistant leukemia cells, we further explored whether or not MARCKS overexpression may serve as a predictive marker of BTZ resistance in clinical samples of acute leukemia patients. To this end, we examined primary patient specimens from a phase II childhood refractory/relapsed ALL trial in which BTZ is administered in two intensive re-induction regimens containing vincristine, prednisone, PEG-asparaginase, doxorubicin or cyclophosphamide and etoposide followed by methotrexate treatment. MARCKS expression was demonstrated in 64% of therapy-refractory pediatric leukemia specimens (n=44) wherein higher MARCKS expression trended (p=0.09) towards a dismal response to BTZ-containing chemotherapy. Finally, from a mechanistic perspective, we showed a concentration-dependent association of MARCKS protein with the emergence of ubiquitin-containing vesicles in the resistant cells. This association with MARCKS protein was lost upon exocytosis of these vesicles, which were found to be extruded and taken up in co-cultures with recipient HeLa cells. Collectively, we propose a role for MARCKS in a novel mechanism of BTZ resistance through vesicular exocytosis of ubiquitinated proteins in BTZ-resistant cells to overcome proteolytic stress over a broad range of cytotoxic BTZ concentrations. Disclosures Kaspers: Janssen-Cilag: Research Funding. Smeets:Novartis: Employment. Zweegman:Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding. Cloos:Takeda: Honoraria.

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Recurrent Mutations in CCND3 Confer Clinical Resistance to FLT3 Inhibitors

Blood ◽

10.1182/blood.v126.23.677.677 ◽

2015 ◽

Vol 126 (23) ◽

pp. 677-677 ◽

Cited By ~ 3

Author(s):

Catherine C. Smith ◽

Aaron D. Viny ◽

Evan S. Massi ◽

Cyriac Kandoth ◽

Nicholas D. Socci ◽

...

Keyword(s):

Board Of Directors ◽

Research Funding ◽

Acquired Resistance ◽

Cyclin D3 ◽

Phase Ii Trials ◽

Advisory Committees ◽

Primary Resistance ◽

Clinical Resistance ◽

Recurrent Mutations ◽

Flt3 Inhibitors

Abstract Background. Activating mutations in FLT3 occur in ~30% of adult acute myeloid leukemia (AML) cases, including internal tandem duplication (ITD) mutations (~25%) and point mutations in the tyrosine kinase domain (KD). In recent years, multiple selective and potent FLT3 inhibitors such as quizartinib, PLX3397, crenolanib and ASP2215 have demonstrated encouraging preliminary clinical activity in FLT3 mutant AML. Both quizartinib (Schiller et al, ASCO 2014) and ASP2215 (Levis et al, ASCO 2015) have reported composite complete remission rates (CRc) as high as ~50% in phase II trials. Despite these high response rates, the majority of patients relapse after initial response (acquired resistance) and a significant proportion of patients also fail to respond at all (primary resistance). On-target resistance due to secondary KD mutations in FLT3 is a common cause of acquired resistance to the clinically active FLT3 inhibitors quizartinib (Smith et al. Nature 2012) and PLX3397 (Smith et al, Cancer Discovery 2015). However, the causes of primary clinical resistance to FLT3 inhibitors have not been characterized. We performed targeted capture based sequencing of sorted pre-treatment blasts from 8 responding (R) and 21 non-responding (NR) patients treated on the phase I/II trial of PLX3397 in FLT3-ITD+ AML. We deeply sequenced the coding regions of 585 genes known to be mutated in hematologic malignancies/solid tumors and identified genes mutated only in NR patients (compared to genes mutated in both R and NR patients). Results. The number of mutations detected in genes other than FLT3 ranged from 2-18 per sample. There was no increase in the number of mutations found in patients with pre-existing hematologic conditions or in NR patients. Surprisingly, one of the most frequently mutated genes observed exclusively in NR patients was CCND3, the gene encoding cyclin D3, which has rarely been reported to be mutated in AML, though it is mutated in 38% of sporadic Burkitt's lymphoma (BL). A total of 4 individual mutations in CCND3 (Q276*, Q280fs, R271fs, and T283A) were identified in 3/21 NR patients (one patient had both Q276* and Q280fs). No CCND3 mutations were found in R patients. The identified mutations were the same mutations commonly found in BL, known to result in a more stable isoform of cyclin D3 and retain sensitivity to CDK4/6 inhibitors (Schmitz et al., Nature 2012). Expression of the Q276* and T283A mutations in FLT3-ITD+ MV4;11 cells conferred resistance to apoptosis induced by several FLT3 inhibitors (PLX3397, AC220 and crenolanib). However, inhibition of CDK4/6 activity in CCND3 mutant MV4;11 cells by either the CDK4/6 inhibitor palbociclib or the combined FLT3-CDK4/6 inhibitor AMG925 (FLX925) was unable to restore sensitivity to FLT3 inhibition. Moreover, CCND3 mutant MV4;11 cells demonstrated no increase in Rb phosphorylation, suggesting resistance to FLT3 inhibitors facilitated by CCND3 mutations is not predicated on CDK4/6 activation of Rb-dependent E2F-mediated transcription. Conclusions. We have identified recurrent mutations in CCND3, a gene not previously known to be commonly mutated in AML, as a novel cause of clinical primary resistance to FLT3 inhibitors in AML. This represents the first report of a specific non-FLT3 dependent mechanism of clinical resistance to FLT3 inhibitors. Unlike in BL, the functional effects of CCND3 mutations in FLT3-ITD+ AML do not appear to be mediated via CDK4/6 activity and is therefore unresponsive to CDK4/6 inhibition. The molecular mechanism(s) of CCND3-mediated resistance to FLT3 inhibitors are currently being investigated. Disclosures Smith: Plexxikon: Research Funding; Astellas: Research Funding. Off Label Use: Investigational use of PLX3397 in AML. Hsu:Plexxikon Inc.: Employment. West:Plexxikon Inc.: Employment. Bollag:Plexxikon Inc.: Employment. Levine:Foundation Medicine: Consultancy; CTI BioPharma: Membership on an entity's Board of Directors or advisory committees; Loxo Oncology: Membership on an entity's Board of Directors or advisory committees. Shah:Bristol-Myers Squibb: Research Funding; Pfizer: Research Funding; Plexxikon Inc.: Research Funding.

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Targeting Autophagy Kinase ULK1 Can Reverse Bcl2 Inhibitor (ABT-199) Induced Autophagy to Overcome Acquired Resistance in Acute Myeloid Leukemia

Blood ◽

10.1182/blood-2018-99-114817 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 3934-3934

Author(s):

Seemana Bhattacharya ◽

Sujan Piya ◽

Qi Zhang ◽

Natalia Baran ◽

Teresa McQueen ◽

...

Keyword(s):

Board Of Directors ◽

Myeloid Leukemia ◽

Research Funding ◽

Acquired Resistance ◽

Advisory Committees ◽

Qrt Pcr ◽

Nsg Mice ◽

Equity Ownership ◽

Acute Myeloid

Abstract Introduction Anti-apoptotic Bcl2 family members mediate resistance to therapies in acute myeloid leukemia (AML)1. The small molecule Bcl2 inhibitor ABT-199 (venetoclax) promotes mitochondria driven intrinsic apoptosis, and in combination with hypomethylating agents or chemotherapy, has been highly promising in the clinic as treatment of AML2-4. The response rate to ABT-199 is very impressive, but acquired resistance is a major problem. Compensatory upregulation of Mcl1 is an important mechanism of such acquired resistance to mitochondrial apoptosis5. Autophagy is vital for mitochondrial health, mediates resistance to apoptosis and is induced by Bcl2 inhibition6. We performed mechanistic studies to address our hypothesis that disabling autophagy by targeting the apical autophagy kinase ULK1 can reverse resistance to ABT-199. Methods ULK1 was genetically modified in OCIAML3 (human AML cell line), by shRNA knockdown (KD) or CRISPR-Cas9 knockout (KO). In addition, AML cell lines (including ABT-199 resistant) and patient samples were treated with ABT-199 and ULK1 inhibitor SBI-02069657. Combination index (CI) for drug synergy was calculated based on Chou-Talalay method8. Drug-treated or genetically manipulated cells were profiled by reverse phase protein array (RPPA), mass cytometry (CyTOF) and gene expression profiling (GEP). Autophagy was detected by LC3 quantification by western blot (WB) and flow cytometry, and monodansylcadaverine assay. Mitochondrial functions were analyzed by Seahorse Cell Mito Stress test, and MTG, TMRE and ROS assays (flow cytometry). For in vivo studies ULK1 KO and corresponding control cells were injected in NSG mice and monitored by bioluminescent imaging (BLI) and quantification of human CD45 cells. Results ABT-199 induced autophagy in OCIAML3 (increase by 175±27%, p=0.01 - LC3 flow; 4X increase in LC3 II/I ratio - WB). Apoptosis induction by ABT-199 was enhanced by ULK1 KD (36±1.9% over control, p<0.01) or KO (77±1.3%, p<0.01). ULK1 inhibitor SBI-0206965 demonstrated high synergy with ABT-199 at inducing apoptosis in OCIAML3 (CI = 0.51, p<0.001) and MOLM13 (CI = 0.24, p<0.001). The combination was also effective in eliminating bulk and CD34+ stem/progenitor cells in primary AML samples (CI - Bulk: 0.69; CD34: 0.74; p<0.05) (Fig 1). Mcl1 was significantly downregulated by ULK1 inhibitor alone and in combination with ABT-199. ULK1 inhibition lowered Mcl1 transcription, as measured by qRT-PCR: 43±0.03% with SBI-0206965 and 63±0.3% in KO cells (both p<0.01). SBI-0206965 inhibited Mcl1 transcription regulators Stat3 and Erk1/2 and enhanced DNA damage in combination with ABT-199 (WB) (Fig 2). Since ABT-199 modulates mitochondrial function, we examined the effect of inhibiting ULK1 in this context. By Seahorse assay, the combination decreased basal OCR and ATP production by 62 and 58% respectively, p<0.01. This was accompanied by an increase in membrane depolarization (TMRE change - OCIAML3: 62%, MOLM13: 82%; p<0.01) and mitochondrial ROS generation (62% increase, p=0.01) compared to control cells (Fig 3). Interestingly, ULK1 inhibition increased mitochondrial mass (30%, p=0.012) by MTG assay, which may be due to impaired mitophagy. Thus, the combination impairs mitochondrial metabolism and function, which results in the observed increase in ROS that may account for the observed DNA damage and apoptosis. CD44/44v is critical for mitigating ROS through reduced glutathione (GSH)9, and ULK1 inhibition lowered CD44/44v transcription (qRT-PCR) and intracellular GSH in AML cells. Corroborating our earlier data, the ABT-199 resistant cells (OCIAML2R & MOLM13R) show enhanced autophagy as compared to parental cells (OCIAML2: 83%, MOLM13: 35% increase; p=0.001 & 0.009). SBI-0206965 reversed ABT-199 induced autophagy and restored ABT-199 sensitivity in these cells (Fig 4). In a pilot in vivo experiment control and ULK1 KO cells were injected in NSG mice and leukemia engraftment was markedly delayed in the ULK1 KO group (Fig 5). The therapeutic combination study is ongoing. Conclusion Results indicate concomitant targeting of autophagy by ULK1 inhibition and Bcl2 inhibition by ABT-199 can overcome acquired resistance to ABT-199. Hence, with the emergence of Bcl2 inhibitors in frontline therapy for AML and efforts at developing ULK1 inhibitors, this study informs the development of novel apoptosis/autophagy targeting approaches to improve AML therapy. Disclosures Konopleva: Stemline Therapeutics: Research Funding; abbvie: Research Funding; Immunogen: Research Funding; cellectis: Research Funding. Andreeff:Daiichi-Sankyo: Consultancy, Patents & Royalties: MDM2 inhibitor activity patent, Research Funding; United Therapeutics: Patents & Royalties: GD2 inhibition in breast cancer ; Aptose: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Research Funding; Jazz Pharma: Consultancy; SentiBio: Equity Ownership; Oncolyze: Equity Ownership; Celgene: Consultancy; Reata: Equity Ownership; Oncoceutics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Eutropics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Astra Zeneca: Research Funding.

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Dual BCL-2/BCL-XL Inhibitor Pelcitoclax (APG-1252) Overcomes Intrinsic and Acquired Resistance to Venetoclax in Multiple Myeloma Cells

Blood ◽

10.1182/blood-2021-149530 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 2655-2655

Author(s):

Leona Yamamoto ◽

Sanika Derebail ◽

Anil Aktas-Samur ◽

Teru Hideshima ◽

Zuzana Chyra ◽

...

Keyword(s):

Multiple Myeloma ◽

Board Of Directors ◽

Cell Lines ◽

Research Funding ◽

Acquired Resistance ◽

Publicly Traded ◽

Advisory Committees ◽

Erk Activation ◽

Simultaneous Inhibition ◽

Bh3 Mimetic

Abstract Multiple myeloma (MM) is marked by several genetic abnormalities, including chromosome translocation t(11;14). Overexpression of anti-apoptotic BCL-2 in t(11;14) MM promotes disease progression, prompting clinical use of the BH3 mimetic and BCL-2 inhibitor venetoclax in combination with proteasome inhibitor therapy. Despite high initial response rates and prolonged progression-free survival, patients commonly relapse. To delineate mechanisms contributing to acquired drug resistance we modeled responses to venetoclax in two highly sensitive MM cell lines (KMS27 and KMS-12PE). Colonies generated from a surviving cell were cultured in high-dose venetoclax to generate monoclonal drug-tolerant expanded persister (DTEP) clones. To determine whether venetoclax resistance in DTEP clones is mediated by transcriptional adaptation via genomic or epigenomic regulation and transcriptional reprogramming, we conducted whole-genome sequencing (WGS) and RNA-seq of the clones. WGS analysis did not show significant differences between parental and resistant clones, but transcriptomic analysis showed shared and unique transcriptome signatures in DTEP clones. Gene set enrichment analysis of the common significantly modulated genes in resistant clones revealed that PKA-ERK-CREB and K-Ras pathway genes were significantly upregulated, whereas apoptotic genes were downregulated in resistant clones compared to parental cells. Importantly, ectopically expressed ERK in venetoclax-sensitive cells conferred a resistant phenotype that was rescued using two specific ERK inhibitors in DTEP clones. These data confirm a key role for ERK activation in acquired venetoclax resistance. Resistant clones were further characterized by reduced mitochondrial priming assessed by dynamic BH3 profiling, with altered expression of anti-apoptotic regulators including MCL-1, BCL-xL, and BCL-W and the replaced BCL-2: BIM complex by both MCL-1 and BCL-xL. Because these data suggested a functional substitution between anti-apoptotic BCL-2 family members in cells with acquired resistance to venetoclax, we next evaluated if MCL-1 or BCL-xL are codependent in MM cells that are insensitive or resistant to venetoclax. Simultaneous inhibition of MCL-1 (via S63845) or BCL-xL (via A155463) and BCL-2 (via venetoclax) increased BIM release and enhanced cell death in resistant clones (vs single agents), with combination index values < 0.3 in all doses. Upregulation of BCL-xL or MCL-1 in MM cells also mediated primary venetoclax resistance independent of genetic hallmarks (e.g. t [11;14]-translocated cells). Thus, simultaneous inhibition of MCL-1 or BCL-xL and BCL-2 triggered synergistic cytotoxicity in MM cell lines intrinsically resistant to venetoclax. These data suggest that combined inhibition of BCL-2 and BCL-xL may overcome venetoclax resistance. However, the dependence of BCL-xL in mature platelets had triggered thrombocytopenia for patients under therapy using BCL-xL inhibitor. To further explore the potential clinical application of targeting BCL-xL, we employed novel BCl-2/BCL-xL dual inhibitor, BH3 mimetic pelcitoclax (APG-1252). Using pro-drug strategy for design, pelcitoclax has limited cell permeability during circulation, and was converted to a more potent metabolite APG-1252-M1 in tumors/tissues. APG-1252-M1 was thus used for in vitro cell based assays. We discovered that APG-1252-M1 induced cytotoxicity in MM cell lines intrinsically resistant to venetoclax (regardless of genetic background or BCL-2:BCL-xL ratio) and also significantly reduced MM cell viability in clones with acquired venetoclax resistance, overcoming ERK activation and decreasing BIM sequestration by BCL-xL. In vivo study using pelcitoclax is ongoing and will be presented at the meeting. In conclusion, we report that venetoclax resistance in MM evolves from outgrowth of persister clones displaying activation of the ERK pathway and a shift in mitochondrial dependency towards BCL-xL, which can potentially be effectively targeted via the novel BCL-2/BCL-xL inhibitor pelcitoclax (APG-1252), which is currently in clinical investigation for solid tumors (NCT03080311). Disclosures Deng: Ascentage Pharma Group: Current Employment. Zhai: Ascentage Pharma Group Inc.: Current Employment, Current equity holder in publicly-traded company, Other: Leadership and other ownership interests, Patents & Royalties, Research Funding; Ascentage Pharma (Suzhou) Co., Ltd.: Current Employment, Current equity holder in publicly-traded company, Other: Leadership and other ownership interests, Patents & Royalties, Research Funding. Anderson: Sanofi-Aventis: Membership on an entity's Board of Directors or advisory committees; Janssen: 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; 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; Pfizer: Membership on an entity's Board of Directors or advisory committees; Scientific Founder of Oncopep and C4 Therapeutics: Current equity holder in publicly-traded company, Current holder of individual stocks in a privately-held company; AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Mana Therapeutics: Membership on an entity's Board of Directors or advisory committees. Munshi: Novartis: Consultancy; Janssen: Consultancy; Adaptive Biotechnology: Consultancy; Takeda: Consultancy; Celgene: Consultancy; Bristol-Myers Squibb: Consultancy; Karyopharm: Consultancy; Oncopep: Consultancy, Current equity holder in publicly-traded company, Other: scientific founder, Patents & Royalties; Amgen: Consultancy; Abbvie: Consultancy; Legend: Consultancy; Pfizer: Consultancy.

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Distinct Gene Expression Signatures in Patients with Richter's Syndrome and Chronic Lymphocytic Leukemia with Prior Exposure to Ibrutinib

Blood ◽

10.1182/blood-2020-136172 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 30-31

Author(s):

Hanyin Wang ◽

Shulan Tian ◽

Qing Zhao ◽

Wendy Blumenschein ◽

Jennifer H. Yearley ◽

...

Keyword(s):

Gene Expression ◽

B Cell ◽

Board Of Directors ◽

Research Funding ◽

Cell Activation ◽

Expression Profiles ◽

Lymphocytic Leukemia ◽

B Cell Activation ◽

Advisory Committees ◽

Upregulated Genes

Introduction: Richter's syndrome (RS) represents transformation of chronic lymphocytic leukemia (CLL) into a highly aggressive lymphoma with dismal prognosis. Transcriptomic alterations have been described in CLL but most studies focused on peripheral blood samples with minimal data on RS-involved tissue. Moreover, transcriptomic features of RS have not been well defined in the era of CLL novel therapies. In this study we investigated transcriptomic profiles of CLL/RS-involved nodal tissue using samples from a clinical trial cohort of refractory CLL and RS patients treated with Pembrolizumab (NCT02332980). Methods: Nodal samples from 9 RS and 4 CLL patients in MC1485 trial cohort were reviewed and classified as previously published (Ding et al, Blood 2017). All samples were collected prior to Pembrolizumab treatment. Targeted gene expression profiling of 789 immune-related genes were performed on FFPE nodal samples using Nanostring nCounter® Analysis System (NanoString Technologies, Seattle, WA). Differential expression analysis was performed using NanoStringDiff. Genes with 2 fold-change in expression with a false-discovery rate less than 5% were considered differentially expressed. Results: The details for the therapy history of this cohort were illustrated in Figure 1a. All patients exposed to prior ibrutinib before the tissue biopsy had developed clinical progression while receiving ibrutinib. Unsupervised hierarchical clustering using the 300 most variable genes in expression revealed two clusters: C1 and C2 (Figure 1b). C1 included 4 RS and 3 CLL treated with prior chemotherapy without prior ibrutinib, and 1 RS treated with prior ibrutinib. C2 included 1 CLL and 3 RS received prior ibrutinib, and 1 RS treated with chemotherapy. The segregation of gene expression profiles in samples was largely driven by recent exposure to ibrutinib. In C1 cluster (majority had no prior ibrutinb), RS and CLL samples were clearly separated into two subgroups (Figure 1b). In C2 cluster, CLL 8 treated with ibrutinib showed more similarity in gene expression to RS, than to other CLL samples treated with chemotherapy. In comparison of C2 to C1, we identified 71 differentially expressed genes, of which 34 genes were downregulated and 37 were upregulated in C2. Among the upregulated genes in C2 (majority had prior ibrutinib) are known immune modulating genes including LILRA6, FCGR3A, IL-10, CD163, CD14, IL-2RB (figure 1c). Downregulated genes in C2 are involved in B cell activation including CD40LG, CD22, CD79A, MS4A1 (CD20), and LTB, reflecting the expected biological effect of ibrutinib in reducing B cell activation. Among the 9 RS samples, we compared gene profiles between the two groups of RS with or without prior ibrutinib therapy. 38 downregulated genes and 10 upregulated genes were found in the 4 RS treated with ibrutinib in comparison with 5 RS treated with chemotherapy. The top upregulated genes in the ibrutinib-exposed group included PTHLH, S100A8, IGSF3, TERT, and PRKCB, while the downregulated genes in these samples included MS4A1, LTB and CD38 (figure 1d). In order to delineate the differences of RS vs CLL, we compared gene expression profiles between 5 RS samples and 3 CLL samples that were treated with only chemotherapy. RS samples showed significant upregulation of 129 genes and downregulation of 7 genes. Among the most significantly upregulated genes are multiple genes involved in monocyte and myeloid lineage regulation including TNFSF13, S100A9, FCN1, LGALS2, CD14, FCGR2A, SERPINA1, and LILRB3. Conclusion: Our study indicates that ibrutinib-resistant, RS-involved tissues are characterized by downregulation of genes in B cell activation, but with PRKCB and TERT upregulation. Furthermore, RS-involved nodal tissues display the increased expression of genes involved in myeloid/monocytic regulation in comparison with CLL-involved nodal tissues. These findings implicate that differential therapies for RS and CLL patients need to be adopted based on their prior therapy and gene expression signatures. Studies using large sample size will be needed to verify this hypothesis. Figure Disclosures Zhao: Merck: Current Employment. Blumenschein:Merck: Current Employment. Yearley:Merck: Current Employment. Wang:Novartis: Research Funding; Incyte: Research Funding; Innocare: Research Funding. Parikh:Verastem Oncology: Honoraria; GlaxoSmithKline: Honoraria; Pharmacyclics: Honoraria, Research Funding; MorphoSys: Research Funding; Ascentage Pharma: Research Funding; Genentech: Honoraria; AbbVie: Honoraria, Research Funding; Merck: Research Funding; TG Therapeutics: Research Funding; AstraZeneca: Honoraria, Research Funding; Janssen: Honoraria, Research Funding. Kenderian:Sunesis: Research Funding; MorphoSys: Research Funding; Humanigen: Consultancy, Patents & Royalties, Research Funding; Gilead: Research Funding; BMS: Research Funding; Tolero: Research Funding; Lentigen: Research Funding; Juno: Research Funding; Mettaforge: Patents & Royalties; Torque: Consultancy; Kite: Research Funding; Novartis: Patents & Royalties, Research Funding. Kay:Astra Zeneca: Membership on an entity's Board of Directors or advisory committees; Acerta Pharma: Research Funding; Juno Theraputics: Membership on an entity's Board of Directors or advisory committees; Dava Oncology: Membership on an entity's Board of Directors or advisory committees; Oncotracker: Membership on an entity's Board of Directors or advisory committees; Sunesis: Research Funding; MEI Pharma: Research Funding; Agios Pharma: Membership on an entity's Board of Directors or advisory committees; Bristol Meyer Squib: Membership on an entity's Board of Directors or advisory committees, Research Funding; Tolero Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Research Funding; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Rigel: Membership on an entity's Board of Directors or advisory committees; Morpho-sys: Membership on an entity's Board of Directors or advisory committees; Cytomx: Membership on an entity's Board of Directors or advisory committees. Braggio:DASA: Consultancy; Bayer: Other: Stock Owner; Acerta Pharma: Research Funding. Ding:DTRM: Research Funding; Astra Zeneca: Research Funding; Abbvie: Research Funding; Merck: Membership on an entity's Board of Directors or advisory committees, Research Funding; Octapharma: Membership on an entity's Board of Directors or advisory committees; MEI Pharma: Membership on an entity's Board of Directors or advisory committees; alexion: Membership on an entity's Board of Directors or advisory committees; Beigene: Membership on an entity's Board of Directors or advisory committees.

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Identifying Factors That Predict for Unplanned Readmissions for Acute Myeloid Leukemia Patients Receiving Consolidation Cytarabine Based Therapies

Blood ◽

10.1182/blood-2019-128807 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 3433-3433

Author(s):

Caitlin Siebenaller ◽

Madeline Waldron ◽

Kelly Gaffney ◽

Brian P. Hobbs ◽

Ran Zhao ◽

...

Keyword(s):

Board Of Directors ◽

Myeloid Leukemia ◽

Research Funding ◽

Smoking Status ◽

Consolidation Therapy ◽

Peripheral Vascular ◽

Consolidation Chemotherapy ◽

Advisory Committees ◽

History Of ◽

Acute Myeloid

Background: Younger patients (pts) with acute myeloid leukemia (AML) who enter a remission after intensive induction chemotherapy routinely receive at least one cycle of consolidation therapy with high dose cytarabine (HiDAC). This is commonly administered over a five-day inpatient stay, after which pts are discharged home as their blood counts nadir. It is thus a natural consequence of therapy that readmission for febrile neutropenia (FN) occurs, which can impact measures of quality and value in this population. Precise descriptions of incidence, type, and severity of infection, if identified, are lacking, and thus it is unknown to what standard cancer centers should be held for anticipated readmission. We measured these rates, and attempted to identify predictive factors for readmission. Methods: Adult AML pts ≥ 18 years of age who received at least one cycle of HiDAC consolidation (1000-3000 mg/m2 for six doses) in 2009-2019 were included. Our primary aim was to identify predictive factors for readmission after the first cycle of consolidation chemotherapy. The following pt characteristics and co-morbid conditions were analyzed: age, gender, body mass index (BMI), smoking status, AML cytogenetic risk status, history of diabetes, peripheral vascular disease, cardiovascular disease, chronic pulmonary disease, hepatic impairment, and other cancers. Secondary aims included: estimating rates of all-cause readmissions among all HiDAC cycles, defining the rate of FN readmissions, estimating rates of intensive care unit (ICU) admissions, clinical (e.g., probable pneumonia per imaging) and microbiologically-documented infections, prophylactic (ppx) medications used, and mortality. Statistical analyses interrogated potential risk factors for evidence of association with hospital readmission after the first cycle of consolidation chemotherapy. Results: We identified 182 AML pts who fit inclusion criteria. The median age was 50 years (range 19-73); 55% were female and 45% were male. Statistical analyses revealed no association with readmission after cycle 1 for cytogenetic risk (p=0.85), history of heart failure (p= 0.67), chronic pulmonary disease (p=1), connective tissue disease (p=0.53), cerebrovascular accident (p=0.63), diabetes (p=0.63), gender (p=0.07), history of lymphoma (p=0.53), other solid tumors (p=0.53), liver disease (p=1), myocardial infarction (p=0.71), peripheral vascular disease (p=1), or smoking status (p= 0.52). For 480 HiDAC cycles analyzed (88% at 3000 mg/m2), the overall readmission rate was 50% (242/480), of which 85% (205/242) were for FN. Those readmissions which were not FN were for cardiac complications (chest pain, EKG changes), non-neutropenic fevers or infections, neurotoxicity, bleeding or clotting events, or other symptoms associated with chemotherapy (nausea/vomiting, pain, etc.). Median time to FN hospital admission was 18 days (range 6-27) from the start of HiDAC. Of the 205 FN readmissions, 57% had documented infections. Of these infections, 41% were bacteremia, 23% fungal, 16% sepsis, 12% other bacterial, and 8% viral. Of 480 HiDAC cycles, ppx medications prescribed included: 92% fluoroquinolone (442/480), 81% anti-viral (389/480), 30 % anti-fungal (142/480), and 3% colony stimulating factor (14/480). Only 7% (14/205) of FN readmissions resulted in an ICU admission, and 1% (3/205) resulted in death. Conclusions: Approximately half of patients treated with consolidation therapy following intensive induction therapy can be expected to be readmitted to the hospital. The majority of FN readmissions were associated with clinical or microbiologically documented infections and are not avoidable, however ICU admission and death associated with these complications are rare. Readmission of AML pts following HiDAC is expected, and therefore, should be excluded from measures of value and quality. Disclosures Waldron: Amgen: Consultancy. Hobbs:Amgen: Research Funding; SimulStat Inc.: Consultancy. Advani:Macrogenics: Research Funding; Abbvie: Research Funding; Kite Pharmaceuticals: Consultancy; Pfizer: Honoraria, Research Funding; Amgen: Research Funding; Glycomimetics: Consultancy, Research Funding. Nazha:Incyte: Speakers Bureau; Abbvie: Consultancy; Daiichi Sankyo: Consultancy; Jazz Pharmacutical: Research Funding; Novartis: Speakers Bureau; MEI: Other: Data monitoring Committee; Tolero, Karyopharma: Honoraria. Gerds:Imago Biosciences: Research Funding; Roche: Research Funding; Celgene Corporation: Consultancy, Research Funding; Pfizer: Consultancy; CTI Biopharma: Consultancy, Research Funding; Incyte: Consultancy, Research Funding; Sierra Oncology: Research Funding. Sekeres:Syros: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Millenium: Membership on an entity's Board of Directors or advisory committees. Mukherjee:Partnership for Health Analytic Research, LLC (PHAR, LLC): Consultancy; McGraw Hill Hematology Oncology Board Review: Other: Editor; Projects in Knowledge: Honoraria; Celgene Corporation: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Honoraria; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Myers Squibb: Speakers Bureau; Takeda: Membership on an entity's Board of Directors or advisory committees.

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Comparable Outcomes between Unrelated Donor (8/8 or 7/8 matched) and Haploidentical Donor for Allogeneic Stem Cell Transplantation in Adult Patients with Severe Aplastic Anemia

Blood ◽

10.1182/blood-2019-130419 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 4619-4619

Author(s):

Jee Yon Shin ◽

Sung-Soo Park ◽

Gi June Min ◽

Silvia Park ◽

Sung-Eun Lee ◽

...

Keyword(s):

Board Of Directors ◽

Research Funding ◽

Acute Gvhd ◽

Chronic Gvhd ◽

Advisory Committees ◽

Sibling Donor ◽

Alternative Donor ◽

Matched Sibling ◽

Grade Ii

Background Either allogeneic hematopoietic stem cell transplantation (SCT) from HLA-matched sibling donor or immunosuppressive therapy (IST) has been recommended as one of the standard treatments for severe aplastic anemia (SAA). Regarding only 30% of chance finding HLA‐matched sibling donor, SCT from an alternative donor including unrelated (URD) or haplo-identical related donor (HAPLO) is considered to be a treatment option after failure to IST in patients who lack of a HLA-matched sibling donor. The aim of this study was to compare the outcomes of URD SCT and HAPLO SCT for SAA patients. Method Consecutive 152 adult patients with SAA who received first SCT between March 2002 and May 2018 were included: 73 of HLA-well-matched (8/8) URD (WM-URD), 34 of HLA-mismatched URD (MM-URD), and 45 of HAPLO. With the intention to have a follow-up period at least 1 year, data were analyzed at May 2019. A conditioning regimen with total body irradiation (TBI) and cyclophosphamide was used for URD-SCT, whereas that with TBI and fludarabine was administered for HAPLO-SCT (Lee et al, BBMT 2011;17:101, Park et al, BBMT 2017;23:1498, Lee et al, Am J Hematol 2018;93:1368). The combination of tacrolimus and methotrexate were used as graft-versus-host disease (GVHD) prophylaxis. Results The median follow-up was 53.4 (range, 0.2-174.1) months. The median age of URD and HAPLO cohort was 30 (range 18-59) and 34 (range 18-59) years, respectively. Except for one and three patients who failed respective a neutrophil and platelet engraftment, other patients achieved neutrophil and platelet engraftments with median 11 and 15 days for WM-URD, 13 and 16.5 days for MM-URD, and 12 and 14 days for HAPLO, respectively. The five-years overall survival (OS), failure-free survival (FFS), and cumulative incidences (CIs) of graft-failure and transplant-related mortality were similar among three groups: 88.3%, 85.5%, 2.7%, and 11.7% for WM-URD; 81.7%, 81.7%, 0%, and 18.3% for MM-URD, and 86.3%, 84.1%, 6.7%, and 9.2% for HAPLO. The 180-days CI of grade II-IV acute GVHD in WM-URD, MM-URD and HAPLO were 35.6%, 52.9%, and 28.9%, respectively; and moderate to severe chronic GVHD were 28.7%, 38.7% and 11.8% in respective cohort. The CI of grade II-IV acute GVHD and moderate to severe chronic GVHD were significantly higher in MM-URD than those in HAPLO (both, p=0.026). ATG is the only factor affecting both grade II-IV acute GVHD (Hazard ratio 0.511, p=0.01) and moderate to severe chronic GVHD (Hazard ratio 0.378, p=0.003) in multivariate analysis. Other complications including CMV DNAemia, hemorrhagic cystitis, invasive fungal disease, secondary malignancy, and sinusoidal obstruction syndrome were similar among three groups. Survival outcomes of a subgroup of ≥ 2 allele MM-URD (n=16) extracted form MM-URD were inferior that of other donor types (n=136): 75.0% vs. 86.9% (p=0.163) for 5-year OS and 75.0% vs. 84.7% (p=0.272) for 5-year FFS. Conclusion This study shows that there were no significant differences between alternative donor sources in the absence of suitable matched sibling donor. Host/donor features and urgency of transplant should drive physician towards the best choice among alternative donor sources for SAA patients treated with SCT. However, selection of ≥ 2 allele MM-URD should not be recommended due to high incidence of GVHD and inferior outcomes. Figure Disclosures Kim: Celgene: Consultancy, Honoraria; Astellas: Consultancy, Honoraria; Hanmi: Consultancy, Honoraria; AGP: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; SL VaxiGen: Consultancy, Honoraria; Novartis: Consultancy; Amgen: Honoraria; Chugai: Honoraria; Yuhan: Honoraria; Sanofi-Genzyme: Honoraria, Research Funding; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Handok: Honoraria; Janssen: Honoraria; Daiichi Sankyo: Honoraria, Membership on an entity's Board of Directors or advisory committees; BL & H: Research Funding; Otsuka: Honoraria. Lee:Alexion: Consultancy, Honoraria, Research Funding; Achillion: Research Funding.

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