scholarly journals Inotuzumab Ozogamicin (Ino) May Overcome the Impact of Philadelphia Chromosome (Ph)-like Phenotype in Adult Patients (pts) with Relapsed/Refractory (R/R) Acute Lymphoblastic Leukemia (ALL)

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1641-1641 ◽  
Author(s):  
Elias Jabbour ◽  
Kathryn G. Roberts ◽  
Koji Sasaki ◽  
Yaqi Zhao ◽  
Chunxu Qu ◽  
...  

Background: Ino showed significant activity in phase II trials in pts with R/R ALL, that was subsequently confirmed in Phase III trial where Ino demonstrated higher response rates and superior overall survival vs standard of care chemotherapy (SOC) in adults with relapsed/refractory B-cell precursor acute lymphoblastic leukemia (R/R ALL).Ph-like or BCR-ABL1-like ALL possesses a gene expression profile similar to that of BCR-ABL1 ALL but lacks the BCR-ABL1 fusion protein. It is characterized by increased expression of hematopoietic stem-cell genes, deletion of B-cell lineage genes and kinase-activating alterations. Ph-like ALL is associated with refractoriness to standard induction/consolidation chemotherapy and poor prognosis. Aim: To evaluate the outcomes of pts with R/R Ph-like ALL treated in phase II trial with Ino monotherapy. Methods: We performed an integrated analysis of whole genome sequencing (to identify sequence mutations, structural variations and DNA copy number alterations), and transcriptome sequencing (RNAseq; to quantify gene expression, determine Ph-like gene expression profile and identify fusions) on 53 patients' samples treated with Ino between June 2010 and September 2012. Results: Fifty-three evaluable pts with R/R ALL with stored baseline samples were analyzed. Pts characteristics are summarized in Table 1. Median age was 50 years. Ino was given as Salvage 1, Salvage 2, and Salvage 3 and beyond in 20 (38%), 18 (34%), and 15 (28%) pts, respectively. Figure 1 reflects the different genomic subgroups identified among 53 evaluable pts. Ph-like gene signature was found in 12 pts (22.6%). Among these 12 pts, 6 had IGH-CRLF2, 2 IGH-EPOR, 1 SNX2-ABL1, and 3 had no fusions identified. The overall response rates (ORR) were 54% [complete remission (CR) 20%, CR with partial hematologic recovery (CRh) 32%, and marrow CR (CRi) 2%]. Among pts with morphologic remission, 46% and 82% achieved minimal residual disease (MRD) negativity at CR and at any time, respectively. The ORR for pts with Ph-like ALL, Ph-positive ALL, ALL with KMT2A, and others were 58% (CR=25%; CRh=33%), 42% (CR=8%; CRh=33%), 57% (CR=14%; CRh=29%; CRi=14%), and 56% (CR=26%; CRh=30%), respectively. The respective overall MRD negativity rates were 71%, 100%, 75%, and 83% (Table 1). The median follow-up was 60 months. The median event-free (EFS) and overall survival (OS) were 3.3 and 5.4 months, respectively. There was no difference in EFS and OS between the subgroups analyzed (P=0.464; P=0.824). The median EFS and OS were 4.5 and 4.5 months for pts with Ph-like, 3.1 and 7.2 months for those with Ph-positive ALL, 2.8 and 4.4 months for those with KMT2A, and 2.2 and 4.6 months for others (Table 1). 21 (40%) pts had subsequent allogeneic stem cell transplant; 6 (50%), 3 (25%), 4 (57%), and 8 (36%) in each subgroup, respectively. The rate of VOD was 3 (6%) with no difference among different subgroups. Conclusion: The current analysis suggest that Ino therapy may overcome the impact of Ph-like phenotype in pts with ALL. Confirmation of these findings in a larger cohort and in frontline ALL patients is needed. Disclosures Jabbour: Takeda: Consultancy, Research Funding; BMS: Consultancy, Research Funding; Adaptive: Consultancy, Research Funding; Amgen: Consultancy, Research Funding; AbbVie: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Cyclacel LTD: Research Funding. Sasaki:Pfizer: Consultancy; Otsuka: Honoraria. Jain:Precision Biosciences: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmacyclics, an AbbVie company: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen Pharmaceuticals, Inc.: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Genentech: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Research Funding; Adaptive Biotechnologies: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Cellectis: Research Funding; AstraZeneca: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Servier: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Incyte: Research Funding; Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; ADC Therapeutics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Verastem: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Ravandi:Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Xencor: Consultancy, Research Funding; Macrogenix: Consultancy, Research Funding; Menarini Ricerche: Research Funding; Selvita: Research Funding; Cyclacel LTD: Research Funding. Short:AstraZeneca: Consultancy; Takeda Oncology: Consultancy, Research Funding; Amgen: Honoraria. Garcia-Manero:Amphivena: Consultancy, Research Funding; Helsinn: Research Funding; Novartis: Research Funding; AbbVie: Research Funding; Celgene: Consultancy, Research Funding; Astex: Consultancy, Research Funding; Onconova: Research Funding; H3 Biomedicine: Research Funding; Merck: Research Funding. Konopleva:Cellectis: Research Funding; Agios: Research Funding; AbbVie: Consultancy, Honoraria, Research Funding; Ascentage: Research Funding; Eli Lilly: Research Funding; Calithera: Research Funding; Stemline Therapeutics: Consultancy, Honoraria, Research Funding; Forty-Seven: Consultancy, Honoraria; Reata Pharmaceuticals: Equity Ownership, Patents & Royalties; Kisoji: Consultancy, Honoraria; Ablynx: Research Funding; Genentech: Honoraria, Research Funding; Amgen: Consultancy, Honoraria; F. Hoffman La-Roche: Consultancy, Honoraria, Research Funding; Astra Zeneca: Research Funding. Mullighan:Illumina: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: sponsored travel; Pfizer: Honoraria, Other: speaker, sponsored travel, Research Funding; AbbVie: Research Funding; Loxo Oncology: Research Funding; Amgen: Honoraria, Other: speaker, sponsored travel. Kantarjian:Actinium: Honoraria, Membership on an entity's Board of Directors or advisory committees; Agios: Honoraria, Research Funding; Ariad: Research Funding; Novartis: Research Funding; Amgen: Honoraria, Research Funding; Immunogen: Research Funding; AbbVie: Honoraria, Research Funding; Astex: Research Funding; BMS: Research Funding; Cyclacel: Research Funding; Daiichi-Sankyo: Research Funding; Pfizer: Honoraria, Research Funding; Jazz Pharma: Research Funding; Takeda: Honoraria.

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 41-42
Author(s):  
Philip C. Amrein ◽  
Karen K. Ballen ◽  
Kristen E. Stevenson ◽  
Traci M. Blonquist ◽  
Andrew M. Brunner ◽  
...  

Introduction: While progress has been made in the treatment of childhood leukemia, the outlook for patients >60 years of age with acute lymphoblastic leukemia (ALL) is poor with complete remission rates (CR) of approximately 60% and 3-year survivals (OS) of less than 15%. Intensified treatment in a later CALGB trial showed little improvement with a CR=61% and 5-year OS=6% (Stock, Cancer 2013). Ixazomib is an oral proteasome inhibitor, which has shown single agent activity and promising combination activity in pediatric ALL patients (Messinger, Blood 2012). We sought to assess the safety and tolerability, as well as early efficacy of adding ixazomib to a current MGH-DFCI/HCC multi-agent regimen for older adults with ALL. Methods: Patients aged 51 to 75 years of age with newly diagnosed B-ALL and T-ALL were screened for eligibility. Patients with mature ALL (including Burkitt's) were excluded. Patients with Philadelphia chromosome positive ALL (BCR-ABL1+) were eligible, and dasatinib was added to the chemotherapy on Day 10 for these patients. The chemotherapy treatment schedule from induction through maintenance is outlined in Table 1. A standard 3 + 3 patient cohort dose escalation design was used to determine the maximum tolerated dose (MTD) of ixazomib during induction for these patients, the primary objective of the trial. After consolidation I, patients in complete remission (CR) with a suitable donor were offered a hematopoietic stem cell transplantation (HSCT) as per institutional guidelines. Those not going to HSCT continued therapy as noted in the table. Results: There were 19 patients with B-ALL enrolled, none with T-ALL. Among these patients, 7 harbored BCR-ABL1 rearrangements. The median age was 65 years, 74% were male, and 90% had a performance status 0 or 1. The MTD was 2.3 mg of ixazomib, as 2 patients at 3.0 mg developed DLT's: a grade 3 peripheral neuropathy and a grade 5 acute kidney injury (Table 2). Grade 3 and 4 toxicities encountered at any time consisted mainly of grade 4 neutropenia in 13 patients and grade 4 thrombocytopenia in 12 patients. One patient experienced grade 3 neutropenia and 5 patients experienced grade 3 thrombocytopenia. Two patients with grade 2 neuropathy did not meet the definition of DLT. Among the 19 patients, 15 (79%, [95% confidence interval (CI), 54-94%]) achieved CR (14) or CRi (1), and 5 patients went on to HSCT. The median follow-up time was 2 years (range, 1-5) for 8 patients remaining alive. The 1-year overall survival estimate was 53% [95% CI, 29-72%], while the 2-year overall survival estimate was 47% [95% CI, 24-67%]. Conclusions: A dose of 2.3 mg of ixazomib in combination with induction chemotherapy among older patients with ALL was well-tolerated and associated with a promising rate of complete remission. Disclosures Amrein: Takeda: Research Funding; AstraZeneca: Consultancy, Research Funding; Amgen: Research Funding. Brunner:Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Research Funding; AstraZeneca: Research Funding; Forty-Seven Inc: Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Novartis: Research Funding. Hobbs:Novartis: Honoraria; Celgene/BMS: Honoraria; Jazz: Honoraria; Constellation: Honoraria, Research Funding; Incyte: Research Funding; Merck: Research Funding; Bayer: Research Funding. Neuberg:Celgene: Research Funding; Pharmacyclics: Research Funding; Madrigak Pharmaceuticals: Current equity holder in publicly-traded company. Fathi:Takeda: Consultancy, Research Funding; Agios: Consultancy, Research Funding; PTC Therapeutics: Consultancy; Amphivena: Consultancy; Astellas: Consultancy; Daiichi Sankyo: Consultancy; Novartis: Consultancy; Newlink Genetics: Consultancy; Pfizer: Consultancy; Blueprint: Consultancy; Trillium: Consultancy; Kura Oncology: Consultancy; Forty Seven: Consultancy; Jazz: Consultancy; Boston Biomedical: Consultancy; BMS/Celgene: Consultancy, Research Funding; Kite: Consultancy; Trovagene: Consultancy; Amgen: Consultancy; Seattle Genetics: Consultancy, Research Funding; Abbvie: Consultancy. OffLabel Disclosure: MLN 9708, ixazomib is FDA approved for multiple myeloma. In this trial it is used to treat acute lymphoblastic leukemia.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 4380-4380
Author(s):  
Luis Antonio Salazar ◽  
Sandra Vanesa Rios ◽  
Angela María Peña ◽  
Maria Luna-Gonzalez ◽  
Mario Andrés Arenas ◽  
...  

Abstract INTRODUCTION Acute lymphoblastic leukemia (ALL) is a clonal hematopoietic disorder that originates from B or T lymphoid progenitors. It affects more frequently children, but prognosis is worse in adults. ALL has a high incidence in Hispanics (Swords R et al. Blood Cancer J. 2016) and is important to identify baseline clinical, sociodemographic, and cytogenetic characteristics in these patients that are relevant for relapse free and overall survival. Reports of Hispanic patients with ALL outsides of the U.S.A are scare but are important to further characterize the impact of this disease in minority populations. OBJETIVE To describe the association between sociodemographic, clinical and immunophenotypic variables with 12-month relapse free survival (RFS) and overall survival (OS) in patients diagnosed and treated for ALL in a Colombian university hospital (FOSCAL). MATERIALS AND METHODS This is a descriptive observational cohort study that included patients older than 18 years with a confirmed diagnosis of ALL treated in a tertiary university hospital between 2013-2020 and that had at least 12 months follow-up after starting treatment. Baseline sociodemographic, clinical, laboratory and immunophenotypic data were collected. Bivariate analyses of both relapse and mortality cumulative incidences at 12 months, with relative risks (RR) and their 95% Confidence intervals were performed, using either chi-square or Fischer exact test when needed. In a second term, bivariate survival analyses through Kaplan-Meier survival function and Hazard ratios were evaluated, using Cox proportional hazards as the main statistical test. RESULTS Among 128 of include patients, the median age at diagnosis was 34 years (range 0-89 years), 54% were men, 6.2% had type 2 Diabetes Mellitus (T2DM), most had an ECOG PS of 0 (72.7%), 31.8% had splenomegaly, 12% had hepatomegaly and 47% presented without organomegalies. The proportion of patients with overweight and obesity were 26.3% and 22.2% respectively. At diagnosis 80.5% and 8.8% of patients had high risk and standard risk ALL, respectively Forty-eight patients had a FAB classification with 58% being ALL-2 and most of the were unclassified. Most cases (81%) had B-cell immunophenotype, with 55% being pre-B-cell and 32% mature B-cell. Twelve percent of patients were Ph+ B-ALL. At 12 months, the proportion of mortality was 34.4%. Most of the patients (83%) did not have major co-morbidities, however patients with T2DM had a significantly inferior survival at 12 months, HR: 3.68 (95%CI 1.54-8.8 P=0.003), as patients older than 35 years (HR: 2.15, 95%CI: 1.14-4.0, P=0.017) (Table 1). CONCLUSIONS Colombian patients with B-cell ALL have similar clinical, immunophenotypic and cytogenetic (Ph+ prevalence) characteristics as seen in other international cohorts. In our cohort patients older than 35 years and subjects with T2DM had inferior survival at 1 year. Further analyses of socioeconomic factors, molecular features and response to specific regimens are needed to have a better understanding of Colombian B-ALL patients. Figure 1 Figure 1. Disclosures Salazar: Amgen: Research Funding. Peña: Amgen: Research Funding. Sandoval-Sus: BMS: Other: Advisory Board, Speakers Bureau; SeaGen, Janssen, MassiveBio, TG: Other: Advisory Board. Sossa: Amgen: Research Funding.


Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 5284-5284
Author(s):  
Anna Ferrari ◽  
Silvia Vitali ◽  
Valentina Robustelli ◽  
Andrea Ghelli Luserna Di Rora ◽  
Simona Righi ◽  
...  

Abstract Background: The heterogeneous and poor survival group of Philadelphia negative (Ph-) B-ALL patients (pts) that doesn't have the most recurrent adult rearrangements (BCR-ABL1 t(9;22); TCF3-PBX1 t(1;19); MLL-AF4 t(4;11)) are collectively referred to as "triple negative" (Ph-/-/-) ALL. CRLF2 is frequently altered in adult B-ALL, especially in Ph-like pts (50-75% of cases). Alterations that lead, in the majority of cases, to a CRLF2 overexpression. Adult pts with CRLF2 upregulated have poor outcome and novel strategies are needed to improve it. Aims: Clustering and biological characterization of Ph-/-/- ALL (that represents 61% of adult B-ALL; Roberts KG, J Clin Oncol. 2016), considering CRLF2 overexpression event, in order to define and assess biomarkers in this subgroup to test new drugs. Patients and Methods: Gene Expression Profiling (GEP; HTA 2.0 Affymetrix) were performed on 55 Ph-/-/- ALL, 29 B-ALL Ph+ at different time point of the disease and on 7 mononuclear cell of healthy donors. Data were normalized with the Expression Console Software. Successively we cluster triple negative GEP data with our validated pipeline, based on CRLF2 upregulation and in the top ten-gene list. Ph-/-/- ALL samples were then characterized for the presence of gene fusions, Copy Number Alterations (CNAs) and mutations using different approaches (TruSight Pancancer-Illumina; MLPA and/or dMLPA-MRC-Holland; SNP Array-Affymetrix; 454 Junior-Roche and PCR). Results: Clustering our Ph-/-/- gene expression data using the impact of the 10 single genes in our cohort, we could identify a defined 2-clusters-subdivision (Gr1 and Gr2; Fig 1A). The Gr2 is characterized by CTGF, CRLF2 and CD200 (Gr2=3C-up; Fig 1B) overexpression and it represents 14.1% of all B-ALL. The Gr2 GEP is similar to Ph+ one. Fusion copy number alteration and mutational screening done, detected that 3C-Up group has a higher frequency of Ph-like associated lesions (primarily CRLF2, JAK2, IL7R mutations or deletion), that mainly affect JAK-STAT pathway. Also IKZF1 and EBF1 deletions are significantly associated to Gr2 (p=0.003; p=0.016). RAS pathway genes are highly affected in Gr1. Molecular characterization shed light on a very heterogeneous scenario especially in the group 1, suggesting the need of a more discerning clustering for this group. In spite of the small number of cases is required, preliminary Gr1 subclustering discerns MLLr and ZNF384 gene expression subgroups. Notably p53 pathway is enriched in both groups but with different deregulated genes: CHEK2 is upregulated in the group1 and CDK6 in the Gr2. CRLF2 and CD200 immunoblotting and CD200 immunohistochemistry preliminary analyses suggest that protein expression of CRFL2 and CD200 are higher in Gr2 in comparison to Gr1. Conclusions: we identified a new signature, related to CRLF2 high expression, to classify Ph-/-/- ALL B-based on 10 genes. 3C-up represents 14.1% of all B-ALL and it is characterized by a) high co-expression of three main genes: CRLF2, CTGF and CD200; b) IKZF1 deletion; c) JAK-STAT pathway mutations/fusions/deletions. Gr1 represents 46.9% of all B-ALL. Gr2 GEP similarity to Ph+ one, suggests that this Gr2 could contain Ph-like pts. This new Ph-/-/- subclassification identify new potential therapeutic targets with available drug (α-CTGF, α-CD200, CDK2, CHK2 and CDK6 inhibitors; tyrosine kinase inhibitors already effective on Ph+ and Ph-like) to test. Supported by: ELN, AIL, AIRC, project Regione-Università 2010-12 (L. Bolondi), FP7 NGS-PTL project, HARMONY project, Fondazione del Monte BO e RA project. Figure. Figure. Disclosures Cavo: Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: 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, Research Funding, Speakers Bureau; AbbVie: 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; GlaxoSmithKline: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Martinelli:Novartis: Speakers Bureau; Abbvie: Consultancy; Jazz Pharmaceuticals: Consultancy; Janssen: Consultancy; Pfizer: Consultancy, Speakers Bureau; Roche: Consultancy; Celgene: Consultancy, Speakers Bureau; Ariad/Incyte: Consultancy; Amgen: Consultancy.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 30-31
Author(s):  
Hanyin Wang ◽  
Shulan Tian ◽  
Qing Zhao ◽  
Wendy Blumenschein ◽  
Jennifer H. Yearley ◽  
...  

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.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1956-1956
Author(s):  
Amy Wang ◽  
Justin Kline ◽  
Wendy Stock ◽  
Satyajit Kosuri ◽  
Andrew S. Artz ◽  
...  

Background:Treatment options are limited for patients (pts) with hematologic malignancies who relapse after allogeneic stem cell transplantation (allo-SCT). We hypothesized that checkpoint inhibitors may offer a novel approach for maintaining remission after allo-SCT. Data from pre-clinical studies have suggested a potential role for PD-1/PD-L1 inhibitors in acute myeloid leukemia (AML) (Zhang et al., Blood 2009), so it is possible that immunomodulation with checkpoint inhibitors could stimulate the donor anti-leukemia immune response and prevent disease relapse. However, the safety of checkpoint blockade early after allografting remains to be established. Methods:We conducted a pilot study to assess the tolerability and efficacy of Nivolumab, a PD-1 inhibitor, as maintenance therapy after allo-SCT (NCT02985554). Pts were eligible if they were post allo-SCT without evidence of relapse or active graft-vs-host disease (GVHD) or history of prior greater than stage I skin acute GVHD. Nivolumab was to be administered intravenously at 1mg/kg every 2 weeks for 4 doses followed by dosing every 12 weeks. Treatment started 4 weeks after routine immunosuppression was discontinued until 2 years after the transplant. The primary objective was to determine the tolerability of Nivolumab on this schedule. Secondary objectives were evaluation of adverse events, relapse, and overall survival. Results:Four pts were enrolled from December 2017 through November 2018. (Table 1)All pts experienced immune-related adverse events (irAE) from Nivolumab, and 2 (50%) pts experienced serious adverse events. (Table 2)One pt developed grade (G) 4 neutropenia soon after the first dose. (Figure 1)The absolute neutrophil count nadired at 20 cells/µL, at which point pegfilgrastim was administered. An interim bone marrow biopsy (BMBx) confirmed no evidence of relapsed disease. Full neutrophil recovery occurred approximately 3 months after the initial dose, and no subsequent toxicities occurred. Another pt developed G3 autoimmune encephalopathy concurrently with G2 transaminitis and G2 thrombocytopenia after one dose of Nivolumab. (Figure 2)Intravenous methylprednisolone (1mg/kg daily for 3 days) and immunoglobulin (2g/kg in 4 divided doses) were administered, followed by a 7-week steroid taper with full resolution of symptoms. Relapsed disease was ruled out by a BMBx. A third pt developed G2 skin rash approximately 10 days after the first dose of Nivolumab. Skin biopsy demonstrated drug hypersensitivity reaction vs GVHD, and the pt was treated with a 3-week prednisone course (starting at 1mg/kg followed by a taper). A mild flare recurred 2 weeks later, which was treated with topical steroids only. However, Nivolumab was not resumed. The fourth pt developed G2 elevated TSH approximately 2 months into therapy and after 4 doses of Nivolumab. Thyroid hormone replacement was initiated with subsequent symptom improvement and normalization of TSH over a 4-month period. As a result of these unexpected severe toxicities, the study was closed to further enrollment, and further Nivolumab administration ceased. Thus far, one pt (#1) relapsed after a total remission duration of 530 days; the remission duration after starting Nivolumab was 318 days. One pt has mild chronic skin GVHD. All 4 patients remain alive with a median overall survival of 2.3 years (range, 1.9-4.7). Conclusions:Even at low doses, the use of Nivolumab as maintenance therapy in the post allo-SCT setting was not tolerable at the current dosing and schedule due to an unexpected number of high grade irAEs. Additional studies of dose and timing after allo-SCT are needed to improve safety and tolerability, in conjunction with correlative studies to better understand the immunomodulatory processes in the post-transplant setting. Disclosures Kline: Merck: Honoraria; Merck: Research Funding. Stock:Kite, a Gilead Company: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Daiichi: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees; Agios: Membership on an entity's Board of Directors or advisory committees; UpToDate: Honoraria; Research to Practice: Honoraria. Artz:Miltenyi: Research Funding. Larson:Agios: Consultancy; Novartis: Honoraria, Other: Contracts for clinical trials; Celgene: Consultancy. Riedell:Novartis: Research Funding; Verastem: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bayer: Honoraria, Speakers Bureau; Kite/Gilead: Honoraria, Research Funding, Speakers Bureau. Bishop:CRISPR Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Kite: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Juno: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Liu:Arog: Other: PI of clinical trial; BMS: Research Funding; Agios: Honoraria; Novartis: Other: PI of clinical trial; Karyopharm: Research Funding. OffLabel Disclosure: Nivolumab used as maintenance therapy in the post-transplant setting


Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 2149-2149
Author(s):  
Romil Patel ◽  
Neeraj Y Saini ◽  
Ankur Varma ◽  
Omar Hasan ◽  
Qaiser Bashir ◽  
...  

Abstract Introduction: The role of autologous hematopoietic stem cell transplantation (auto-HCT) in the management of patients with Waldenström Macroglobulinemia (WM), a rare, indolent lymphoma, has not been established. We had previously published our experience with auto-HCT in a small cohort of WM patients1. Here, we present an updated analysis of auto-HCT with a larger cohort of WM patients. Methods and study population: The study cohort was comprised of 29 patients who underwent high-dose chemotherapy and auto-HCT at MD Anderson Cancer Center (MDACC). The Kaplan-Meier method was used to create survival curves. Overall survival (OS) was defined as the duration from date of transplant to death or last date of follow-up in living patients. Progression-free survival (PFS) was defined as the duration from date of transplant to either progressive disease or death, whichever occurred first. Results: Median age at auto-HCT was 60 (range, 43-75 years). Eight patients (28%) had concurrent light chain amyloidosis (AL). Of the five patients who had MYD88 testing completed, 3 were positive for the MYD88 mutation. Additionally, of these 3 patients, 2 were also positive for CXCR4 mutation. Patients received a median of 2 lines (range 1-6) of therapy prior to auto-HCT; 3(10%) patients had primary refractory disease, 8(28%) were in first remission, and 18 (62%) had relapsed disease. Median time from transplant to last follow-up for the surviving patients was 5.3 years. Preparative regimens received by the patients were: Melphalan (n=20), BEAM-R (n=2), Busulfan/Melphalan (n=1), Cyclophosphomaide/Etoposide/total body irradiation (n=1), Thiotepa/Busulfan/Cyclophosphamide (n=1), and Carmustine/Thiotepa (n=1). Three patients further went on to receive allogeneic transplant either after relapse from auto-HCT or due to disease transformation to aggressive lymphoma. Twenty-eight patients achieved engraftment with a median time to neutrophil engraftment of 11 days (range, 10-15 days). One patient suffered primary graft failure due to progression of disease and died 84 days after transplant. Non-relapse mortality was 3.4% at 1 year. All patients were eligible for response evaluation. The median OS from diagnosis was 12.2 years. Overall response rate was 96%: complete response (n=8, 27.6%), very good partial response (n=5, 17.3%), partial response (n=15, 51.7%), and progressive disease (n=1, 3.4%). PFS and OS at 5 years were 43.3% and 62.9%, respectively. Median PFS and OS from auto-HCT were 4.1 and 7.3 years (Fig. 1A). The median OS from auto-HCT in first remission + primary refractory and relapsed disease was 8.2 years and 4.1 years, respectively.16 patients were alive at the time of censoring while 13 patients had died. Causes of death include relapsed disease (n=6), secondary malignancy (n=2), infection (n=1), chronic graft-versus-host disease (n=1), and unknown (n=3). 8 patients (28%) were positive for concurrent AL amyloidosis. The sites of amyloid involvement were kidneys (n=2), lungs (n=1), bone marrow (n=1), heart(n=1), lymph nodes(n=1), gastrointestinal tract (n=1) and subcutaneous fat aspirate(n=5). The median overall survival for patients with amyloid involvement (n=8) was 12 years. On univariate analyses, the number of chemotherapy regimens prior to transplant (≤ 2 vs >2 lines) was the strongest predictor of overall survival (p=0.03, HR 0.3, CI: 0.09-0.9, log-rank) and PFS (p=0.001, HR 0.24, CI: 0.07-0.85, log-rank). The median PFS in patients with ≤ 2 lines and > 2 lines of therapy was 71 months versus 19 months, respectively (Fig. 1B). Conclusion: Auto-HCT is safe and feasible in selected patients with WM, with a high response rate and durable remission even in patients with relapsed or refractory disease. References: Krina Patel et.al. Autologous Stem Cell Transplantation in Waldenstrom's Macroglobulinemia. Blood 2012 120:4533; Disclosures Thomas: Celgene: Research Funding; Bristol Myers Squibb Inc.: Research Funding; Acerta Pharma: Research Funding; Array Pharma: Research Funding; Amgen Inc: Research Funding. 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. Orlowski:Takeda: Consultancy; Celgene: Consultancy; Spectrum Pharma: Research Funding; Janssen: Consultancy; Kite Pharma: Consultancy; Sanofi-Aventis: Consultancy; BioTheryX: Research Funding; Amgen: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy. Champlin:Otsuka: Research Funding; Sanofi: Research Funding. Patel:Poseida Therapeutics, Inc.: Research Funding; Takeda: Research Funding; Abbvie: Research Funding; Celgene: Research Funding.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3816-3816 ◽  
Author(s):  
Ryan J. Daley ◽  
Sridevi Rajeeve ◽  
Charlene C. Kabel ◽  
Jeremy J. Pappacena ◽  
Sarah E. Stump ◽  
...  

Introduction: Asparaginase (ASP) has demonstrated a survival benefit in pediatric patients (pts) with acute lymphoblastic leukemia (ALL) and is now part of standard-of-care frontline treatment. As a result, asparaginase preparations have been incorporated into the treatment of adult ALL to improve outcomes. Pegaspargase (PEG-ASP), a modified version of asparaginase with prolonged asparagine depletion, appears to be safe in adults up to age 40 (Stock, et al., Blood, 2019), but is associated with a unique spectrum of toxicities, the risks of which appear to increase with age. Therefore, the safety of PEG-ASP remains a significant concern in older adults w/ ALL. Methods: We conducted a single center retrospective chart review of pts age ≥40 years who received PEG-ASP as part of frontline induction/consolidation or reinduction, between March 2008 and June 2018 at Memorial Sloan Kettering Cancer Center. The primary objective was to evaluate the tolerability and toxicity of PEG-ASP based on the incidence and severity of ASP-related toxicities (hypersensitivity reactions, hypertriglyceridemia, hyperbilirubinemia, transaminitis, pancreatitis, hypofibrinogenemia, etc) according to the Common Terminology Criteria for Adverse Events, version 4.03. Laboratory values recorded were either the peak or the nadir, the more appropriate for toxicity assessment, within a 4-week period following PEG-ASP administration. Secondary objectives were to determine the total number of doses of PEG-ASP administered in comparison to the number of doses intended, and to characterize the rationale for PEG-ASP discontinuation when applicable. Fisher's exact test was used to compare the incidence of PEG-ASP toxicities with respect to pt and treatment characteristics (regimen, age, BMI, gender, Philadelphia chromosome positive (Ph+) vs. Ph-, presence of extramedullary disease, PEG-ASP dose). P values were not adjusted for multiple comparisons. Results: We identified 60 pts with ALL (40 B-ALL and 20 T-ALL) who received at least one dose of PEG-ASP. Nine pts were Ph+. The median pt age at initiation of the treatment was 53, (range, 40 to 80), and 19 pts had a BMI ≥30 kg/m2. Forty-four pts received treatment for newly diagnosed ALL, and 16 pts for relapsed disease. Table 1 lists pt baseline characteristics. Among the 44 pts with newly diagnosed ALL, 27 pts received PEG-ASP as part of pediatric or pediatric-inspired regimens at doses of 2000 - 2500 units/m2, and 1 pt received a modified dose of 1000 units/m2 due to age. The remaining 16 pts received PEG-ASP at doses of 1000 - 2000 units/m2 for consolidation, per established adult regimens (ALL-2 and L-20; Lamanna, et al., Cancer, 2013). Grade 3/4 ASP-related toxicities with a >10% incidence included: hyperbilirubinemia, transaminitis, hypoalbuminemia, hyperglycemia, hypofibrinogenemia, and hypertriglyceridemia. Frontline treatment regimens in which PEG-ASP was used in consolidation cycles only (ALL-2, L-20) were associated w/ a lower incidence of hyperbilirubinemia (p=0.009) and hypertriglyceridemia (p<0.001) compared to those regimens that included PEG-ASP during induction (pediatric/pediatric-inspired regimens) (Table 2). Younger age (40-59 vs. ≥60 years) was associated with a greater risk of hypertriglyceridemia (p<0.001) and higher PEG-ASP dose (≥2000 vs. <2000 units/m2) was associated with a greater risk of hypertriglyceridemia and hypofibrinogenemia (p=0.002 and p=0.025, respectively). Thirty-eight pts (63%) received all intended doses of PEG-ASP. Six pts stopped PEG-ASP to proceed to allogeneic hematopoietic stem cell transplantation (5 in CR1, 1 in CR2), and 7 pts stopped for hypersensitivity reactions. Hepatotoxicity was the only ASP-related toxicity that led to PEG-ASP discontinuation occurring in 5 pts (hyperbilirubinemia, N=4; transaminitis, N=1). The total number of intended doses of PEG-ASP based on regimens used was 186, and 112 were administered. Conclusion: PEG-ASP was incorporated into the treatment of 60 adult ALL pts age ≥40, with manageable toxicity. Seven pts discontinued PEG-ASP due to hypersensitivity reactions and 5 discontinued due to hepatotoxicity, but other reported toxicities did not lead to PEG-ASP discontinuation and the majority of the pts completed all intended doses of PEG-ASP. This study suggests that with careful monitoring, PEG-ASP can safely be administered in adults ≥40 years of age. Disclosures Rajeeve: ASH-HONORS Grant: Research Funding. Tallman:UpToDate: Patents & Royalties; Oncolyze: Consultancy, Membership on an entity's Board of Directors or advisory committees; Delta Fly Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Rigel: Consultancy, Membership on an entity's Board of Directors or advisory committees; Cellerant: Research Funding; Tetraphase: Consultancy, Membership on an entity's Board of Directors or advisory committees; Nohla: Consultancy, Membership on an entity's Board of Directors or advisory committees; BioLineRx: Consultancy, Membership on an entity's Board of Directors or advisory committees; Orsenix: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; ADC Therapeutics: Research Funding; Biosight: Research Funding; Jazz Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; KAHR: Consultancy, Membership on an entity's Board of Directors or advisory committees; Daiichi-Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees. Geyer:Dava Oncology: Honoraria; Amgen: Research Funding. Park:Takeda: Consultancy; Allogene: Consultancy; Amgen: Consultancy; AstraZeneca: Consultancy; Autolus: Consultancy; GSK: Consultancy; Incyte: Consultancy; Kite Pharma: Consultancy; Novartis: Consultancy.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 2742-2742
Author(s):  
Christian Hurtz ◽  
Gerald Wertheim ◽  
Rahul S. Bhansali ◽  
Anne Lehman ◽  
Grace Jeschke ◽  
...  

Background: Research efforts have focused upon uncovering critical leukemia-associated genetic alterations that may be amenable to therapeutic targeting with new drugs. Targeting the oncogenic BCR-ABL1 fusion protein in Philadelphia chromosome-positive B-cell acute lymphoblastic leukemia (B-ALL) with tyrosine kinase inhibitors to shut down constitutive signaling activation and induce leukemia cell cytotoxicity has remarkably improved patients' survival and has established a precision medicine paradigm for kinase-driven leukemias. However, multiple subtypes of B-ALL are driven through non-tyrosine fusion proteins, including the high-risk KMT2A-rearranged (KMT2A-R) subtype common in infants with B-ALL, leaving many patients with insufficient treatment options. Objectives: KMT2A-R B-ALL is associated with chemoresistance, relapse, and poor survival with a frequency of 75% in infants and 10% in older children/adults with B-ALL. Current intensive multiagent chemotherapy regimens induce significant side effects yet fail to cure the majority of patients, demonstrating continued need for novel therapeutic approaches. The goals of our study were to i) identify signaling molecules required for KMT2A-R B-ALL cell survival, ii) select ALL-associated targets that are not essential in normal tissues, and iii) develop new treatment strategies that may benefit patients with KMT2A-R ALL. Results: We performed a genome-wide kinome CRISPR screen using the pediatric KMT2A-R cell line SEM and identified DYRK1A among other signaling molecules as required for leukemia cell survival. DYRK1A is a member of the dual-specificity tyrosine phosphorylation-regulated kinase family and has been reported as a critical oncogene in a murine Down syndrome (DS) model of megakaryoblastic leukemia. In normal hematopoiesis, DYRK1A controls the transition from proliferation to quiescence during lymphoid development. Deletion of DYRK1A results in increased numbers of B cells in S-G2-M phase, yet also significantly reduces cell proliferation. Meta-analysis of ChIP-Seq data from two KMT2A-AFF1 cell lines (SEM and RS4;11) and a human KMT2A-Aff1-FLAG-transduced ALL model demonstrates that both N-terminal (KMT2AN) and C-terminal (AFF1C) and the FLAG-tagged KMT2A-Aff1 fusion directly bind to the DYRK1A promoter. Gene expression and RT-PCR analyses of SEM cells treated with inhibitors against two important KMT2A fusion complex proteins, DOT1L (histone methyltransferase) and menin (tumor suppressor), demonstrate that only menin inhibition induced DYRK1A downregulation. Interestingly, deletion of germline KMT2A in murine B-cells did not decrease DYRK1A expression. Taken together, these results suggest direct transcriptional regulation through the KMT2A fusion complex. Surprisingly, RNA and protein expression of DYRK1A was reduced in KMT2A-R ALL compared to other B-ALL subtypes. We then identified MYC as a potential negative regulator of DYRK1A that could explain the lower RNA and protein expression levels observed. A gain-of-function experiment showed marked downregulation of DYRK1A when MYC was ectopically expressed in murine B-cells, while loss of MYC resulted in DYRK1A upregulation. Parallel analysis of publicly available gene expression data from children with high-risk B-ALL (NCI TARGET database) showed significantly higher MYC RNA expression levels in KMT2A-R ALL as compared to other ALL subtypes, further validating our findings that MYC acts as a negative regulator of DYRK1A. Finally, to assess pharmacologic inhibition, we treated multiple KMT2A-rearranged ALL cell lines with the novel DYRK1A inhibitor EHT 1610 and identified sensitivity to DYRK1A inhibition. We then queried the Achilles database and identified that DYRK1A is not a common essential gene in normal tissues, suggesting minimal potential for on-target/off-tumor effects of DYRK1A inhibition. Conclusions: We identified a novel mechanism in KMT2A-R ALL in which DYRK1A is positively regulated by the KMT2A fusion protein and negatively regulated by MYC. Genetic deletion and pharmacologic inhibition of DYRK1A resulted in significant growth disadvantage of KMT2A-R ALL cells. While further studies are needed, we predict that combining DYRK1A inhibitors with chemotherapy could decrease relapse risk and improve long-term survival of patients with KMT2A-R B-ALL. Disclosures Crispino: MPN Research Foundation: Membership on an entity's Board of Directors or advisory committees; Sierra Oncology: Consultancy; Scholar Rock: Research Funding; Forma Therapeutics: Research Funding. Tasian:Incyte Corportation: Research Funding; Gilead Sciences: Research Funding; Aleta Biotherapeutics: Membership on an entity's Board of Directors or advisory committees. Carroll:Astellas Pharmaceuticals: Research Funding; Incyte: Research Funding; Janssen Pharmaceuticals: Consultancy.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 9-9
Author(s):  
Shanye Yin ◽  
Gregory Lazarian ◽  
Elisa Ten Hacken ◽  
Tomasz Sewastianik ◽  
Satyen Gohil ◽  
...  

A hotspot mutation within the DNA-binding domain of IKZF3 (IKZF3-L162R) has been identified as a putative driver in chronic lymphocytic leukemia (CLL); however, its functional effects are unknown. We recently confirmed its role as a CLL driver in a B cell-restricted conditional knock-in model. IKZF3 mutation altered mature B cell development and signaling capacity, and induced CLL-like disease in elderly mice (~40% penetrance). Moreover, we found IKZF3-L162R acts as a gain-of-function mutation, altering DNA binding specificity and target selection of IKZF3, and resulting in overexpression of multiple B-cell receptor (BCR) genes. Consistent with the murine data, RNA-sequencing analysis showed that human CLL cells with mut-IKZF3 [n=4] have an enhanced signature of BCR-signaling gene expression compared to WT-IKZF3 [n=6, all IGHV unmutated] (p&lt;0.001), and also exhibited general upregulation of key BCR-signaling regulators. These results confirm the role of IKZF3 as a master regulator of BCR-signaling gene expression, with the mutation contributing to overexpression of these genes. While mutation in IKZF3 has a clear functional impact on a cardinal CLL-associated pathway, such as BCR signaling, we note that this driver occurs only at low frequency in patients (~3%). Because somatic mutation represents but one mechanism by which a driver can alter a cellular pathway, we examined whether aberrant expression of IKZF3 could also yield differences in BCR-signaling gene expression. We have observed expression of the IKZF3 gene to be variably dysregulated amongst CLL patients through re-analysis of transcriptomic data from two independent cohorts of human CLL (DFCI, Landau et al., 2014; ICGC, Ferreira et al., 2014). We thus examined IKZF3 expression and BCR-signaling gene expression, or the 'BCR score' (calculated as the mean expression of 75 BCR signaling-associate genes) in those cohorts (DFCI cohort, n=107; ICGC cohort, n=274). Strikingly, CLL cells with higher IKZF3 expression (defined as greater than median expression) had higher BCR scores than those with lower IKZF3 expression (&lt;median) (p=0.0015 and p&lt;0.0001, respectively). These findings were consistent with the notion that IKZF3 may act as a broad regulator of BCR signaling genes, and that IKZF3 overexpression, like IKZF3 mutation, may provide fitness advantage. In support of this notion, our re-analysis of a gene expression dataset of 107 CLL samples (Herold Leukemia 2011) revealed that higher IKZF3 expression associated with poorer prognosis and worse overall survival (P=0.035). We previously reported that CLL cells with IKZF3 mutation appeared to increase in cancer cell fraction (CCF) with resistance to fludarabine-based chemotherapy (Landau Nature 2015). Instances of increase in mut-IKZF3 CCF upon treatment with the BCR-signaling inhibitor ibrutinib have been reported (Ahn ASH 2019). These studies together suggest an association of IKZF3 mutation with increased cellular survival following either chemotherapy or targeted treatment. To examine whether higher expression of IKZF3 was associated with altered sensitivity to ibrutinib, we performed scRNA-seq analysis (10x Genomics) of two previously treatment-naïve patients undergoing ibrutinib therapy (paired samples, baseline vs. Day 220). We analyzed an average of 11,080 cells per patient (2000 genes/cell). Of note, following ibrutinib treatment, remaining CLL cells expressed higher levels of IKZF3 transcript compared to pretreatment baseline (both p&lt;0.0001), whereas no such change was observed in matched T cells (n ranging between 62 to 652 per experimental group, p&gt;0.05), suggesting that cells with high expression of IKZF3 were selected by ibrutinib treatment. Moreover, we showed that ibrutinib treatment resulted in consistent upregulation of BCR-signaling genes (e.g., CD79B, LYN, GRB2, FOS, RAC1, PRKCB and NFKBIA) (n ranging between 362 to 1374 per experimental group, all p&lt;0.0001), which were likewise activated by mutant IKZF3. Altogether, these data imply that IKZF3 mutation or overexpression may influence upregulation of BCR-signaling genes and enhance cellular fitness even during treatment with BCR-signaling inhibitors. We highlight our observation that IKZF3 mutation appears to be phenocopied by elevated IKZF3 expression, and suggest that alterations in mRNA or protein level that mimic genetic mutations could be widespread in human cancers. Disclosures Kipps: Pharmacyclics/ AbbVie, Breast Cancer Research Foundation, MD Anderson Cancer Center, Oncternal Therapeutics, Inc., Specialized Center of Research (SCOR) - The Leukemia and Lymphoma Society (LLS), California Institute for Regenerative Medicine (CIRM): Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Honoraria, Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Genentech/Roche: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; VelosBio: Research Funding; Oncternal Therapeutics, Inc.: Other: Cirmtuzumab was developed by Thomas J. Kipps in the Thomas J. Kipps laboratory and licensed by the University of California to Oncternal Therapeutics, Inc., which provided stock options and research funding to the Thomas J. Kipps laboratory, Research Funding; Ascerta/AstraZeneca, Celgene, Genentech/F. Hoffmann-La Roche, Gilead, Janssen, Loxo Oncology, Octernal Therapeutics, Pharmacyclics/AbbVie, TG Therapeutics, VelosBio, and Verastem: Membership on an entity's Board of Directors or advisory committees. Wu:BionTech: Current equity holder in publicly-traded company; Pharmacyclics: Research Funding.


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