Early Changes in Cytokines, Chemokines and Indices of Bone Metabolism in a Phase 2 Study of the Bruton Tyrosine Kinase (Btk) Inhibitor, Ibrutinib (PCI-32765) in Patients with Relapsed or Relapsed/Refractory Multiple Myeloma (MM)

Abstract Abstract 4039 Introduction: Bruton tyrosine kinase (Btk) is essential in the development and function of B cells through normal B cell receptor signaling, and it is down-regulated in non-malignant plasma cells. This is not the case in malignant plasma cells of patients with MM where robust Btk gene expression is usual. In addition, Btk is expressed and functional in osteoclasts and their precursors, which play a pathogenic role in MM-related bone disease, as well as growth and survival of MM in the microenvironment. Researchers in our group (Tai, Chang et al, Blood, 2012) recently demonstrated that the Btk inhibitor ibrutinib (PCI-32765) inhibited the interaction of MM cells with stromal cells, and inhibited the growth in vitro of MM colony forming cells from patient explants. Ibrutinib suppressed in vitro osteoclast differentiation and production of multiple cytokines and chemokines including CCL3, CCL4, IL-8, and TGF-β. Ibrutinib furthermore decreased MM progression and accompanying bone destruction in an in vivo SCID-Hu myeloma model. Based on these observations, we initiated a clinical trial of ibrutinib in patients with relapsed (R) and relapsed/refractory (R/R) MM. This report of early marker changes is based upon 7 patients who have completed 3 cycles of treatment. Methods: Patients with progressive disease (PD) after at least 2 prior lines of therapy received a fixed dose of oral ibrutinib 420 mg orally once daily, with a cycle defined as 28 days. Dexamethasone 40 mg weekly could be added if no response or PD was observed by cycle 2. Blood levels of cytokines, chemokines and bone markers (bone-specific alkaline phosphatase (bAP), sclerostin and RANKL) were assessed centrally at Days 1, 2, 8, and 15 of Cycle 1, Cycle 2 Day 1 and every 2 cycles thereafter, by single or multiplexed immunoassays. Serum cross-linked C-terminal peptide of collagen I (sCTx) was determined by a central lab at the start of Cycles 1 and 2 and every other cycle thereafter. Responses were assessed following the International Myeloma Working Group criteria (modified to include minimal response). Results: Thirteen patients [M/F: 8/5; median age 62, range 49–74 years] were enrolled between March 21 and June 6, 2012. All patients had received prior treatment with lenalidomide, bortezomib, alkylators and dexamethasone. 7 were refractory to their last treatment. At the time of data cut off, 7 of the 13 patients enrolled had completed 3 cycles of therapy and were the ones used for analysis. Over the course of three cycles, several markers relevant to bone metabolism exhibited gradual decreases. At Cy4D1 plasma RANKL, sclerostin, and bAP exhibited (median) decreases of 47%, 39%, and 36%, respectively. Relative changes in sCTx were more variable at Cy2D1, but there appeared to be a trend towards subject-by-subject decreases at C4D1 (Fig. 1). Factors promoting growth and angiogenesis (e.g. VEGF, EGF, and FGF) and cytokines and chemokines (CCL3, CCL4, TNFα, Groα and MDC) with roles in MM micro-environmental interactions exhibited similar reductions (Fig. 2). Among these the most dramatic and consistent changes were in CCL3 and CCL4, chemokines enhancing adhesive interactions contributing to osteolysis in MM, which showed median decreases of 43% and 77% at Cy4D1, respectively. Ibrutinib has been uniformly well tolerated and the safety experience to date has been similar to that noted in other studies of ibrutinib in lymphoma and CLL. Conclusions: Early reductions in blood levels of cytokines, chemokines, markers of bone metabolism, and pro-angiogenic and growth factors, were observed among MM patients treated with ibrutinib, which were consistent with pre-clinical studies. Among markers related to bone metabolism, it appeared that changes in regulatory molecules (sclerostin, RANKL) were more marked and perhaps preceded changes in markers of osteoclast (sCTx) or osteoblast (bAP) activity. Elucidation of these patterns and their significance will require longer follow-up of a larger number of patients. These results indicate that ibrutinib can exert significant biologic effects on the microenvironment in MM. Clinical correlations will be forthcoming based upon maturing results over the next several months. Disclosures: Vij: Millennium: Speakers Bureau; Celgene: Research Funding, Speakers Bureau; Onyx: Honoraria, Research Funding. Chang:Pharmacyclics, Inc.: Employment, Equity Ownership. Huff:Celgene: Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy. Chang:Pharmacyclics, Inc.: Employment, Equity Ownership. Moussa:Pharmacyclics, Inc.: Employment, Equity Ownership. Buggy:Pharmacyclics: Employment, Equity Ownership. Elias:Pharmacyclics, Inc.: Employment, Equity Ownership. Richardson:Millenium Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Celgene Corporation: Membership on an entity's Board of Directors or advisory committees; Novartis Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Johnson & Johnson: 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.

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Novel Protein Agonist of Thrombopoiesis Acts Via a Physiocrine Pathway Distinct From That of Thrombopoietin

Blood ◽

10.1182/blood.v118.21.2376.2376 ◽

2011 ◽

Vol 118 (21) ◽

pp. 2376-2376

Author(s):

Minh-Ha T Do ◽

Wei Zhang ◽

Kyle Chiang ◽

Chi-Fang Wu ◽

Chulho Park ◽

...

Keyword(s):

Bone Marrow ◽

Board Of Directors ◽

Employment Equity ◽

Advisory Committees ◽

Platelet Production ◽

Platelet Counts ◽

Normal Platelet ◽

Naturally Occurring ◽

Equity Ownership

Abstract Abstract 2376 Thrombopoietin (TPO) is recognized as the main regulator of platelet production, yet its genetic ablation in mice does not completely obliterate thrombopoiesis, suggesting that alternate pathways could lead to platelet formation. We recently identified a naturally-occurring protein that acts as a potent agonist of platelet production by a mechanism distinct from that of TPO. This protein belongs to a novel class of human extracellular signaling proteins called physiocrines that are generated from tRNA synthetases by alternative splicing or proteolysis. Physiocrines interact with several classes of receptors through unique mechanisms to modulate cellular differentiation and tissue homeostasis in normal and pathological processes. The newly identified thrombopoietic physiocrine, termed ATYR0030, is an engineered version of a naturally-occurring physiocrine derived from the tyrosyl tRNA synthetase (YRS). In vivo, systemic administration of ATYR0030 or YRS physiocrine to rats led to an increase in platelets counts comparable to that seen with TPO treatment, but with a greater effect in animals with low baseline platelet levels. When injected into normal animals preselected for low platelet counts, ATYR0030 treatment resulted in an increase in platelets up to, but not beyond, normal levels (Figure 1), suggesting a role in platelet homeostasis and differentiating its effects from the known activity of TPO. Intravenous administration of ATYR0030 also accelerated recovery of platelet counts in carboplatin-treated rats, indicating a possible role in bone marrow reconstitution after chemical insult. Consistent with homeostatic properties, no toxicity was seen in a repeat-dose 28-day non-GLP safety study in rats dosed up to 100-fold above the efficacious range. Histopathology assessment revealed no tissue abnormalities, no increase in bone marrow reticulin and no hyperplasia of myeloid precursors. Clinical chemistry and hematology parameters were in the normal range with a modest increase in platelet counts, as anticipated in animals with normal platelet levels. Our in vitro data suggest that ATYR0030 may play a role in megakaryopoiesis by facilitating cell migration and adhesion to the vasculature. In contrast to TPO, ATYR0030 does not directly signal through the TPO receptor and does not activate the JAK/STAT pathway but rather appears to engage specific G-protein coupled receptors. In vitro, ATYR0030 does not stimulate proliferation of cultured M07e human megakaryoblasts or primary bone marrow cells isolated from AML patients (Figure 2). The parent synthetase is present in human platelets and is secreted in response to platelet activation, perhaps providing a feedback mechanism to stimulate the release of new platelets. In an effort to link the biological activity of ATYR0030 and the role that the parent synthetase plays in human physiology, we have begun to analyze samples from patients with abnormal platelets counts to determine circulating levels of the parent synthetase. The unique thrombopoietic activity of ATYR0030 may lead to an orthogonal approach to restoring normal platelet levels in thrombocytopenic patients who currently have limited treatment options. For example, in the myelodysplastic syndrome population, TPO-receptor agonists carry a risk of stimulating blast proliferation and accelerating disease progression to acute myeloid leukemia (AML). The distinct proliferation profile of ATYR0030 may translate into important safety benefits by reducing the risk of progression to AML. In addition, the potential role of ATYR0030 in regulating platelet homeostasis may provide a greater safety margin in the normalization of platelet levels, thereby also limiting the risk of thrombosis. Leveraging the therapeutic potential of this thrombopoietic physiocrine may lead to the development of a novel treatment option with a favorable safety profile. Disclosures: Do: aTyr Pharma: Employment, Equity Ownership, Patents & Royalties. Zhang:aTyr Pharma: Employment, Equity Ownership. Chiang:aTyr Pharma: Employment, Equity Ownership. Wu:aTyr Pharma: Employment, Equity Ownership, Patents & Royalties. Park:aTyr Pharma: Equity Ownership. Yang:aTyr Pharma: Consultancy, Equity Ownership, Patents & Royalties, Research Funding. Kunkel:aTyr Pharma: Consultancy, Stock Ownership. Ashlock:aTyr Pharma: Employment, Equity Ownership. Mendlein:aTyr Pharma: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties. Belani:Atyr Pahrma: Consultancy, Equity Ownership, Patents & Royalties. Vasserot:aTyr Pharma: Employment, Equity Ownership, Patents & Royalties. Watkins:aTyr Pharma: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees.

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Combination of Selinexor and the Proteasome Inhibitor, Bortezomib Shows Synergistic Cytotoxicity in Diffuse Large B-Cells Lymphoma Cells In Vitro and In Vivo

Blood ◽

10.1182/blood.v128.22.4131.4131 ◽

2016 ◽

Vol 128 (22) ◽

pp. 4131-4131 ◽

Cited By ~ 3

Author(s):

Trinayan Kashyap ◽

Irfana Muqbil ◽

Amro Aboukameel ◽

Boris Klebanov ◽

Ramzi Mohammad ◽

...

Keyword(s):

Cell Cycle ◽

Board Of Directors ◽

Nuclear Export ◽

Transcriptional Activity ◽

Employment Equity ◽

Advisory Committees ◽

Nuclear Retention ◽

Equity Ownership

Abstract Background: XPO1 (exportin-1/CRM1) mediates nuclear export of proteins containing leucine-rich amino-acid consensus sequences. XPO1 cargo proteins include many of the major tumor suppressor proteins (p53, IkB, pRB, FOXOs) and their export leads to the inactivation of cell cycle checkpoints. Overexpression of XPO1 has been reported to correlate with poor cancer prognosis. The Selective Inhibitor of Nuclear Export (SINE) compound, selinexor, binds covalently to the cargo pocket on XPO1, inhibits nuclear export which leads to cell cycle arrest and specific cancer cell death. Selinexor is currently in advanced clinical trials for patients with solid and hematological malignancies including patients with relapsed/refractory Diffuse Large B-Cell Lymphoma (DLBCL) (NCT02227251). Using preclinical models, we recently demonstrated that proteasome inhibitors (PI) can re-sensitize multiple myeloma that acquired resistance to selinexor. Here, we aimed to find if treatment with selinexor and bortezomib is beneficial for the treatment of DLBCL. Methods: DLBCLcell lines were treated with selinexor in combination with bortezomib. Cell viability was examined using standard viability assays after 72 hours of treatment. Whole cell protein lysates were evaluated by immunoblotting. NF-κB transcriptional activity was analyzed using an ELISA assay. WSU-DLCL2 cells were grown as sub-cutaneous tumors in ICR SCID mice. Tumor bearing mice were divided into 4 groups and were administered either vehicle, sub-maximum tolerated doses of selinexor (10 mg/kg p.o. twice a week, M, Th), bortezomib (1 mg/kg i.v. twice a week, M, TH) and the combination of selinexor (10 mg/kg p.o. twice a week) plus bortezomib (1 mg/kg i.v. twice a week). Results: The combination treatment of selinexor with bortezomib synergistically killed DLBCL cells compared to the single agents alone. Co-treatment with bortezomib enhanced selinexor mediated nuclear retention of IκB-α. Selinexor plus bortezomib treatment decreased NF-κB transcriptional activity. Finally, the combination of selinexor with bortezomib showed superior anti-tumor efficacy in the combination group compared to single agent treatments in WSU-DLCL2 xenograft model. Conclusions: Based on our results, inhibition of NF-κB transcriptional activity through forced nuclear retention of IκB appears to be an important mechanism underlying the synergistic effects of selinexor plus bortezomib in many different cell lines including DLBCL. The superior efficacy of selinexor plus bortezomib combination both in vitro and in vivo when compared to single agents along provides a rational for conducting clinical trials with these combinations in DLBCL patients. Disclosures Kashyap: Karyopharm Therapeutics: Employment, Equity Ownership. Klebanov:Karyopharm Therapeutics: Employment, Equity Ownership. Senapedis:Karyopharm Therapeutics: Employment, Equity Ownership. Shacham:Karyopharm Therapeutics: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Kauffman:Karyopharm Therapeutics Inc: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Landesman:Karyopharm Therapeutics: Employment, Equity Ownership.

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In Vitro and in Vivo Quantification of Exportin-1 (XPO1) Occupancy By the Oral Selective Inhibitor of Nuclear Export (SINE) Selinexor in Multiple Myeloma, Acute Myeloid Leukemia, and Healthy PBMCs

Blood ◽

10.1182/blood.v124.21.5196.5196 ◽

2014 ◽

Vol 124 (21) ◽

pp. 5196-5196

Author(s):

Marsha Crochiere ◽

Boris Klebanov ◽

Erkan Baloglu ◽

Ori Kalid ◽

Trinayan Kashyap ◽

...

Keyword(s):

Board Of Directors ◽

Nuclear Export ◽

Drug Exposure ◽

Employment Equity ◽

Advisory Committees ◽

Hel Cells ◽

Equity Ownership ◽

Cargo Binding

Abstract Introduction: SINE are a family of small molecules that selectively inhibit nuclear export by forming a slowly reversible covalent bond with Cysteine 528 (Cys528) in the cargo binding pocket of Exportin 1 (XPO1/CRM1). SINE binding to XPO1 leads to forced nuclear retention and activation of major tumor suppressor proteins (TSPs) such as p53, FOXO, pRB and IkB, resulting in selective death of cancer cells. Selinexor is an orally bioavailable SINE compound currently in human phase I and II clinical trials for advanced hematological and solid cancers. Oral selinexor demonstrates maximal pharmacokinetic exposure at 1-2 hours in humans with associated increases in pharmacodynamic markers of XPO1 inhibition in 2-4 hours that last for up to 48 hours. The goal of this study was to develop a binding assay that would enable quantification of XPO1 occupancy in PBMCs from patients following oral administration of selinexor. Methods: To measure the binding of SINE to XPO1, biotinylated leptomycin B (LMB) was utilized. Biotinylated LMB binds covalently and irreversibly to Cys528 in the cargo-binding site of free XPO1 with activity confirmed to be similar to that of unmodified LMB in cytotoxicity assays. To measure SINE binding to XPO1 in vitro, cancer cell lines and PBMCs from normal human donors were treated with SINE compounds prior to treatment with biotinylated LMB. Any XPO1 that did not bind SINE instead binds to biotinylated LMB and can be quantified. In in vivo studies, mice were treated with selinexor, followed by collection of PBMCs for treatment with biotinylated LMB. After incubation with biotinylated LMB, cells were harvested, lysed, and protein lysates were subjected to pull-down experiments with streptavidin-conjugated beads followed by immunoanalysis of XPO1. Results: To evaluate selinexor-XPO1 binding kinetics in vitro, MM.1S, AML2, AML3, and HEL cells were treated with 0 - 10 µM of SINE compounds and unbound XPO1 was pulled down from cell lysates treated with biotinylated LMB. Immunoanalysis showed that 50% XPO1 occupancy with selinexor was achieved at 0.07 µM in MM.1S, 0.1 µM in AML2, 0.03 µM in AML3, and 0.12 µM in HEL cells. Selinexor-XPO1 occupancy experiments using human PBMCs isolated from donor whole blood showed 50% XPO1 occupancy at 0.05 µM. In mice, 50% XPO1 occupancy in PMBCs was achieved after 4 hours treatment with 1.2 mg/kg (3.6 mg/m2) selinexor, while 90% XPO1 occupancy was achieved at 8.1 mg/kg (24.3 mg/m2). Mice treated with a single dose of selinexor from 1.5 to 10 mg/kg for 4-96 hours revealed sustained, dose dependent XPO1 occupancy in PBMCs for up to 72 hours. Conclusions: We have developed a sensitive and robust assay to measure selinexor binding to XPO1 that can be used to evaluate drug exposure following treatment with oral selinexor in preclinical and clinical studies. Studies are ongoing to determine whether there is a correlation between XPO1 occupancy (pharmacodynamics measurement) with disease response in patients with solid and hematological malignancies. Disclosures Crochiere: Karyopharm: Employment. Klebanov:Karyopharm Therpeutics: Employment. Baloglu:Karyopharm: Employment. Kalid:Karyopharm Therapeutics: Employment. Kashyap:Karyopharm Therapeutics: Employment. Senapedis:Karyopharm: Employment. del Alamo:Karyopharm: Employment. Rashal:Karyopharm Therapeutics: Employment. Tamir:Karyopharm: Employment. McCauley:Karyopharm Therapeutics: Employment, Equity Ownership. Carlson:Karyopharm Therapeutics: Employment. Savona:Karyopharm: Consultancy, Equity Ownership; Gilead: Consultancy; Incyte: Consultancy; Celgene: Consultancy. Kauffman:Karyopharm Therapeutics, Inc: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties. Shacham:Karyopharm Therapeutics, Inc: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties. Landesman:Karyopharm Therapeutics: Employment.

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The Human CD38 Monoclonal Antibody Daratumumab Improves the Anti-Myeloma Effect of Lenalidomide with Dexamethasone in Vitro

Blood ◽

10.1182/blood.v118.21.5106.5106 ◽

2011 ◽

Vol 118 (21) ◽

pp. 5106-5106

Author(s):

Michel de Weers ◽

Michael van der Veer ◽

Berris van Kessel ◽

Joost M Bakker ◽

Shulamiet Wittebol ◽

...

Keyword(s):

Research Funding ◽

Plasma Cells ◽

Ex Vivo ◽

Poor Responders ◽

Employment Equity ◽

Advisory Committees ◽

Complement Dependent Cytotoxicity ◽

Equity Ownership ◽

Made In

Abstract Abstract 5106 Multiple myeloma (MM) represents an incurable malignancy of antibody-producing clonal plasma cells. Over the past decade significant progress has been made in MM treatment using novel immunomodulating agents such as lenalidomide (LEN) and bortezomib (BORT). Daratumumab (DARA) is a human CD38 antibody with broad spectrum killing activity. DARA mediates MM cell death via ADCC (antibody dependent cellular cytotoxicity), CDC (complement dependent cytotoxicity) and apoptosis. We are currently exploring the possibility to further improve MM therapy by combining novel MM therapeutics with DARA. Our initial in vitro work already showed significantly improved MM cell killing by combining DARA with LEN and BORT treatment, especially in patient samples which showed poor responses to the LEN-BORT combination. We now investigated whether DARA can also further improve therapy of lenalidomide or bortezomib in combination with corticosteroids. In ex vivo assays, which allow us to address MM cell lysis directly in BM-MNC isolated from MM patients, DARA significantly enhanced killing of MM cells that were treated with LEN or dexamethasone (DEX). Importantly, DARA was also able to enhance lysis of MM cells that were poor responders to the LEN-DEX combination. This suggests that patients might benefit from a DARA-LEN-DEX combination therapy. Experiments showing effects of DARA on killing of BORT-DEX treated cells are currently underway. The results of this study extend our previous results with LEN-BORT-DARA, showing that MM cells lysis is enhanced by DARA, especially in in samples from patients that are refractory or poorly responding to existing and novel emerging combination therapies. These results support the hypothesis that powerful and complementary effects may be achieved when DARA is combined with LEN and cortocosteroids in clinical MM studies. Disclosures: Weers: Genmab: Employment, Equity Ownership, Patents & Royalties. Veer:Genmab: Research Funding. van Kessel:Genmab: Research Funding. Bakker:Genmab: Employment, Equity Ownership. Parren:Genmab: Employment, Equity Ownership, Patents & Royalties. Lokhorst:Genmab: Membership on an entity's Board of Directors or advisory committees, Research Funding. Mutis:Genmab: Research Funding.

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Inhibition Of Nuclear Transport Modulator Xpo1/CRM1 For The Treatment Of Acute Myeloid Leukemia (AML)

Blood ◽

10.1182/blood.v122.21.237.237 ◽

2013 ◽

Vol 122 (21) ◽

pp. 237-237 ◽

Cited By ~ 2

Author(s):

Michael P. Rettig ◽

Matthew Holt ◽

Julie Prior ◽

Sharon Shacham ◽

Michael Kauffman ◽

...

Keyword(s):

Flow Cytometry ◽

Board Of Directors ◽

Cell Lines ◽

Nuclear Export ◽

Employment Equity ◽

Advisory Committees ◽

Ic50 Values ◽

Equity Ownership

Abstract Background Exportin 1 (XPO1) also called CRM1, is a widely expressed nuclear export protein, transporting a variety of molecules including tumor suppressor proteins and cell cycle regulators. Targeted inhibition of XPO1 is a new strategy to restore multiple cell death pathways in various malignant diseases. SINEs are novel, orally available, small molecule Selective Inhibitors of Nuclear Export (SINE) that specifically bind to XPO1 and inhibit its function. Methods We used WST-1 cell proliferation assays, flow cytometry, and bioluminescence imaging to evaluate the efficacy of multiple SINEs to induce apoptosis alone and in combination with cytarabine (AraC) or doxorubicin in vitro in chemotherapy sensitive and resistant murine acute promyelocytic leukemia (APL) cells. This murine model of APL was previously generated by knocking in the human PML-RARa cDNA into the 5’ regulatory sequence of the cathepsin G locus (Westervelt et al. Blood, 2003). The abnormal co-expression of the myeloid surface antigen Gr1 and the early hematopoietic markers CD34 and CD117 identify leukemic blasts. These Gr1+CD34+CD117+ APL cells partially retain the ability to terminally differentiate toward mature granulocytes (mimicking more traditional AML models) and can be adoptively transferred to secondary recipients, which develop a rapidly fatal leukemia within 3 weeks after tumor inoculation. To assess the safety and efficacy of SINEs in vivo, we injected cryopreserved APL cells intravenously via the tail vein into unconditioned genetically compatible C57BL/6 recipients and treated leukemic and non-leukemic mice (n=15/cohort) with 15 mg/kg of the oral clinical staged SINE KPT-330 (currently in Phase 1 studies in patients with solid tumors and hematological malignancies) alone or in combination with 200 mg/kg cytarabine every other day for a total of 2 weeks. Peripheral blood was obtained weekly from mice for complete blood counts and flow cytometry to screen for development of APL. Results The first generation SINE, KPT214, inhibited the proliferation of murine APL cell lines in a dose and time dependent manner with IC50 values ranging from of 95 nM to 750 nM. IC50 values decreased 2.4-fold (KPT-185) and 3.5-fold (KPT-249) with subsequent generations of the SINEs. Consistent with the WST-1 results, Annexin V/7-aminoactinomycin D flow cytometry showed a significant increase of APL apoptosis within 6 hours of KPT-249 application. Minimal toxicity against normal murine lymphocytes was observed with SINEs even up to doses of 500 nM. Additional WST-1 assays using AraC-resistant and doxorubicin-resistant APL cell lines demonstrated cell death of both chemotherapy-resistant cell lines at levels comparable to the parental chemosensitive APL cell lines. Combination therapy with low dose KPT-330 and AraC showed additive effects on inhibition of cell proliferation in vitro. This additive effect of KPT-330 and chemotherapy on APL killing was maintained in vivo. As shown in Figure 1, treatment with AraC or KPT-330 alone significantly prolonged the survival of leukemic mice from a median survival of 24 days (APL + vehicle) to 33 days or 39 days, respectively (P < 0.0001). Encouragingly, combination therapy with AraC + KPT-330 further prolonged survival compared to monotherapy (P < 0.0001), with some mice being cured of the disease. Similar in vivo studies with the AraC-resistant and doxorubicin-resistant APL cells are just being initiated. Conclusions Our data suggests that the addition of a CRM1 inhibitor to a chemotherapy regimen offers a promising avenue for treatment of AML. Disclosures: Shacham: Karyopharm Therapeutics Inc.: Employment, Equity Ownership, Membership on an entity’s Board of Directors or advisory committees, Patents & Royalties. Kauffman:Karyopharm Therapeutics Inc.: Employment, Equity Ownership, Membership on an entity’s Board of Directors or advisory committees, Patents & Royalties. McCauley:Karyopharm Therapeutics, Inc: Employment, Equity Ownership.

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Antithrombin Reduction Corrected Thrombin Generation in Samples from Hemophilia A and B Patients with Inhibitors

Blood ◽

10.1182/blood.v126.23.552.552 ◽

2015 ◽

Vol 126 (23) ◽

pp. 552-552 ◽

Cited By ~ 3

Author(s):

Gili Kenet ◽

Tami Livnat ◽

Emma Fosbury ◽

Pratima Chowdary ◽

Alfica Sehgal ◽

...

Keyword(s):

Board Of Directors ◽

Research Funding ◽

Thrombin Generation ◽

Hemophilia A ◽

Severe Hemophilia ◽

Employment Equity ◽

Advisory Committees ◽

Advisory Boards ◽

Equity Ownership

Abstract Background: Severe hemophilia A and B patients with inhibitors experience serious musculoskeletal hemorrhage as well as high risk of limb and life threatening bleeds. However, lack of effect of FVIII or FIX substitution therapy and short functional half-life of by-passing agents, leave these patients with very limited bleed preventive treatment options. ALN-AT3 (Alnylam Pharmaceuticals, Cambridge, MA, USA), a subcutaneously administered investigational RNAi therapeutic targeting reduction of antithrombin for potential treatment of hemophilia is currently in phase 1 clinical development in hemophilia A and B patients without inhibitors. Initial data from that ongoing study in 12 patients suggest an AT KD dependent correction of thrombin generation. This study aims to assess changes in peak thrombin generation in samples from patients with severe hemophilia A and B with inhibitors following in vitro reduction of antithrombin. Materials and methods: Citrated plasma samples were obtained from patients with severe hemophilia A and B with high responding inhibitors. Samples were spiked in vitro with isotype specific control IgG or a monoclonal antibody (Haemtech Inc, Essex Junction, VT, USA) targeting antithrombin knockdown of 50% and 90%. Dynamic formation of thrombin was measured by calibrated automated thrombin generation using 1pM tissue factor PPP reagent and 4μM phospholipid (Thrombinoscope, Maastricht, The Nederlands). The primary effect measure was peak thrombin (nM). Data were tested by a 1-way ANOVA and p<0.05 was considered statistically significant. Results: A total of 12 inhibitor hemophilia samples were investigated; 9 hemophilia A and 3 hemophilia B. All the control samples demonstrated a profound defect in thrombin generation with a median peak thrombin of 19.9 nM (range 6.7 - 42.4). Patients with severe hemophilia A and inhibitors had a median peak thrombin generation of 19.7 nM (range 6.7 - 42.4), whereas patients with severe hemophilia B and inhibitors had a median peak thrombin generation of 19.2nM (range 19.4 - 38.1). An AT reduction dependent improvement in peak thrombin generation was observed in all 12 tested plasma samples (Figure 1). In the first 12 subjects, peak thrombin generation was increased up to 363% from a mean of 22nM (control) to 39 nM (50% AT reduction) and 80nM (90% AT reduction) (p<0.05); levels comparable to thrombin generation observed in healthy male volunteers and in hemophilia patients treated with ALN-AT3. Conclusions: These in vitro data suggest that reduction of AT is a promising approach for restoring hemostatic balance and correcting thrombin generation in hemophilia patients with inhibitors. Furthermore, the present laboratory data compare well with clinical data generated with ALN-AT3 administered to patients with hemophilia A or B. Thus, both laboratory and emerging clinical data suggest that targeting antithrombin could be a promising approach for restoring hemostatic balance in hemophilia. The potential for low volume subcutaneous administration, infrequent dosing, and applicability to persons with hemophilia who have inhibitors, make ALN-AT3 a particularly encouraging investigational therapy. Figure 1. Figure 1. Disclosures Kenet: Bayer, Novo Nordisk: Other: Advisory Boards, Speakers Bureau; Opko Biologics: Consultancy, Other: Advisory Boards; BPL; Baxelta: Research Funding; Pfizer: Honoraria. Off Label Use: ALN-AT3 is an investigational RNAi therapeutic targeting the endogenous anticoagulant antithrombin.. Chowdary:Sobi: Membership on an entity's Board of Directors or advisory committees; CSL Behring: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novo Nordisk: Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding; Baxalta: Membership on an entity's Board of Directors or advisory committees; Biogen: Membership on an entity's Board of Directors or advisory committees. Sehgal:Alnylam Pharmaceuticals: Employment, Equity Ownership. Akinc:Alnylam Pharmaceuticals: Employment, Equity Ownership. Sorensen:Alnylam Pharmaceuticals: Employment, Equity Ownership.

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Calmodulin Inhibition Rescues the Effects of Ribosomal Protein Deficiency in in Vitro and In Vivo Diamond Blackfan Anemia Models

Blood ◽

10.1182/blood.v126.23.672.672 ◽

2015 ◽

Vol 126 (23) ◽

pp. 672-672

Author(s):

Elizabeth R Macari ◽

Alison Taylor ◽

David Raiser ◽

Kavitha Siva ◽

Katherine McGrath ◽

...

Keyword(s):

Ribosomal Protein ◽

Board Of Directors ◽

Transcriptional Activity ◽

Employment Equity ◽

Advisory Committees ◽

In Vivo Models ◽

Diamond Blackfan Anemia ◽

Equity Ownership

Abstract Ribosomal protein (RP) mutations are found in many diseases, including Diamond Blackfan anemia (DBA), where defective erythropoiesis, craniofacial abnormalities and increased cancer risk are major complications. RP mutations cause p53 activation through accumulation of free RPs that bind and sequester MDM2, the negative regulator of p53. We previously characterized a zebrafish mutant in rps29, a gene found mutated in DBA patients. Rps29-/- embryos have hematopoietic and endothelial defects, including decreased cmyb and flk1 expression and defects in hemoglobinization. Consistent with other animal models of RP dysfunction, p53 knockdown in rps29-/- embryos rescued these defects. To uncover novel compounds that correct the phenotypes of DBA, we performed a chemical screen in rps29-/- embryos. Several structurally distinct calmodulin (CaM) inhibitors successfully rescued hemoglobin (Hb) levels in the mutant embryo. To confirm that CaM inhibitors could rescue mammalian models of DBA, we applied them to human and murine models. Treating cord blood-derived CD34+ cells deficient in RPS19 with the CaM inhibitor, trifluoperazine (TFP), relieved the erythroid differentiation block. Injection of TFP in a DBA murine model significantly increased red blood cell number and Hb levels. Mechanistic studies in A549 cells infected with lentivirus expressing RPS19 shRNA demonstrated that TFP blocks p53 nuclear accumulation and induction of multiple p53 transcriptional target genes (p<0.05). Through p53 genetic manipulation, we determined that TFP inhibits p53 transcriptional activity through its c-terminal domain (CTD). Since this region has many residues that can be phosphorylated by CaM-dependent kinases, we hypothesized that TFP blocked phosphorylation of residues in the CTD. To test this hypothesis, phosphomimetic mutants were transfected into Saos2 cells and p53 transcriptional activity in response to TFP was evaluated using p21mRNA levels. TFP treatment of cells containing WT p53 or a transactivation domain mutant, S15D, resulted in a 4-fold reduction in p21 mRNA levels, while all four phosphomimetic mutants in the CTD had attenuated responses to TFP (<2-fold). The common CaM-dependent kinases that phosphorylate these CTD residues are Chk1 and Chk2. Investigation of the role of Chk1 and Chk2 found that a chk2 morpholino and multiple inhibitors of Chk2, but not Chk1, rescued Hb levels in the rps29-/- embryo (p<0.05). Chk2 inhibitors also mimic CaM inhibition in our in vitro assays. In conclusion, we have shown a novel mechanism by which CaM inhibitors mediate p53 activity through the CTD and can rescue the phenotypes of multiple in vitro and in vivo models of DBA. Our data strongly suggests that CaM or Chk2 inhibitors may be effective therapies for DBA patients, and a clinical trial is being planned with TFP. Disclosures Ebert: Genoptix: Consultancy, Patents & Royalties; H3 Biomedicine: Consultancy; Celgene: Consultancy. Zon:FATE Therapeutics: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Other: Founder; Scholar Rock: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Other: Founder.

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Crowdsourced High-Risk Classifiers for Multiple Myeloma Patients Commonly Identify PHF19 As a Robust Progression Biomarker

Blood ◽

10.1182/blood-2019-127362 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 4370-4370

Author(s):

Michael J Mason ◽

Carolina D. Schinke ◽

Christine Eng ◽

Fadi Towfic ◽

Fred Gruber ◽

...

Keyword(s):

Gene Expression ◽

Multiple Myeloma ◽

High Risk ◽

Disease Progression ◽

Board Of Directors ◽

Research Funding ◽

Plasma Cells ◽

Employment Equity ◽

Advisory Committees ◽

Equity Ownership

Multiple myeloma (MM) is a hematological malignancy of terminally differentiated plasma cells residing within the bone marrow with 25,000-30,000 patients diagnosed in the United States each year. The disease's clinical course depends on a complex interplay chromosomal abnormalities and mutations within plasma cells and patient socio-demographic factors. Novel treatments extended the time to disease progression and overall survival for the majority of patients. However, a subset of 15%-20% of MM patients exhibit an aggressive disease course with rapid disease progression and poor overall survival regardless of treatment. Accurately predicting which patients are at high-risk is critical to designing studies with a better understanding of myeloma progression and enabling the discovery of novel therapeutics that extend the progression free period of these patients. To date, most MM risk models use patient demographic data, clinical laboratory results and cytogenetic assays to predict clinical outcome. High-risk associated cytogenetic alterations include deletion of 17p or gain of 1q as well as t(14;16), t(14;20), and most commonly t(4,14), which leads to juxtaposition of MMSET with the immunoglobulin heavy chain locus promoter, resulting in overexpression of the MMSET oncogene. While cytogenetic assays, in particular fluorescence in situ hybridization (FISH), are widely available, their risk prediction is sub-optimal and recently developed gene expression based classifiers predict more accurately rapid progression. To investigate possible improvements to models of myeloma risk, we organized the Multiple Myeloma DREAM Challenge, focusing on predicting high-risk, defined as disease progression or death prior to 18 months from diagnosis. This effort combined 4 discovery datasets providing participants with clinical, cytogenetic, demographic and gene expression data to facilitate model development while retaining 4 additional datasets, whose clinical outcome was not publicly available, in order to benchmark submitted models. This crowd-sourced effort resulted in the unbiased assessment of 171 predictive algorithms on the validation dataset (N = 823 unique patient samples). Analysis of top performing methods identified high expression of PHF19, a histone methyltransferase, as the gene most strongly associated with disease progression, showing greater predictive power than the expression level of the putative high-risk gene MMSET. We show that a simple 4 feature model composed of age, stage and the gene expression of PHF19 and MMSET is as accurate as much larger published models composed of over 50 genes combined with ISS and age. Results from this work suggest that combination of gene expression and clinical data increases accuracy of high risk models which would improve patient selection in the clinic. Disclosures Towfic: Celgene Corporation: Employment, Equity Ownership. Dalton:MILLENNIUM PHARMACEUTICALS, INC.: Honoraria. Goldschmidt:Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; John-Hopkins University: Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Mundipharma: Research Funding; Amgen: Consultancy, Research Funding; Chugai: Honoraria, Research Funding; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Molecular Partners: Research Funding; MSD: Research Funding; Sanofi: Honoraria, 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; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Adaptive Biotechnology: Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Research Funding; Dietmar-Hopp-Stiftung: Research Funding; John-Hopkins University: Research Funding. Avet-Loiseau:takeda: Consultancy, Other: travel fees, lecture fees, Research Funding; celgene: Consultancy, Other: travel fees, lecture fees, Research Funding. Ortiz:Celgene Corporation: Employment, Equity Ownership. Trotter:Celgene Corporation: Employment, Equity Ownership. Dervan:Celgene: Employment. Flynt:Celgene Corporation: Employment, Equity Ownership. Dai:M2Gen: Employment. Bassett:Celgene: Employment, Equity Ownership. Sonneveld:SkylineDx: Research Funding; Takeda: Honoraria, Research Funding; Karyopharm: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; BMS: Honoraria; Amgen: Honoraria, Research Funding. Shain:Amgen: 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; Janssen: Membership on an entity's Board of Directors or advisory committees; AbbVie: Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees; Sanofi Genzyme: Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Consultancy. Munshi:Abbvie: Consultancy; Takeda: Consultancy; Oncopep: Consultancy; Celgene: Consultancy; Adaptive: Consultancy; Amgen: Consultancy; Janssen: Consultancy. Morgan:Bristol-Myers Squibb, Celgene Corporation, Takeda: Consultancy, Honoraria; Celgene Corporation, Janssen: Research Funding; Amgen, Janssen, Takeda, Celgene Corporation: Other: Travel expenses. Walker:Celgene: Research Funding. Thakurta:Celgene: Employment, Equity Ownership.

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Histone Deacetylase Inhibitors: Potent Inducers of Tumor Latent EBV Thymidine Kinase Induction

Blood ◽

10.1182/blood.v116.21.1831.1831 ◽

2010 ◽

Vol 116 (21) ◽

pp. 1831-1831

Author(s):

Douglas V Faller ◽

Sajal K Ghosh ◽

Susan P Perrine ◽

Robert M Williams ◽

Ronald J Berenson

Keyword(s):

Board Of Directors ◽

Tumor Cells ◽

Hydroxamic Acid ◽

Short Chain Fatty Acids ◽

Lymphoma Cells ◽

Employment Equity ◽

Advisory Committees ◽

Lymphoid Malignancies ◽

Equity Ownership

Abstract Abstract 1831 Strong epidemiological association of Epstein-Barr Virus (EBV) with various human lymphoid malignancies and in vitro studies demonstrating tumorigenic activity of many EBV latent gene products suggest a causal relationship between EBV and these diseases. However, as EBV maintains a latent state of infection in these lymphomas, typical anti-herpesviral drugs, such as the nucleoside analogs ganciclovir (GCV) or acyclovir, are ineffective as these pro-drugs require expression of a lytic phase EBV protein, thymidine kinase (TK), for their activity. Therefore, selective induction of EBV lytic-phase gene expression in lymphoma cells that harbor latent EBV, coupled with simultaneous exposure to anti-herpesviral drugs, has been advanced as promising targeted therapy, because of resulting targeting of cytotoxicity to the EBV-infected tumor cells. A variety of agents including short-chain fatty acids and chemotherapeutic drugs, have been used to induce EBV lytic-phase infection in cultured cells, but these in vitro studies have generally not translated into clinical application. We have successfully used arginine butyrate and GCV to treat EBV-positive lymphoid malignancies in a recent Phase I/II clinical trial. In this study of 15 patients with relapsed or refractory EBV-positive lymphoid tumors, 4 patients achieved complete tumor remissions and 6 patients partial tumor remissions. However, the rapid metabolism of butyrate requires continuous IV administration of high doses. Butyrate has pan-HDAC inhibitory activity, and we have established that this activity is responsible for the induction of the EBV-TK protein. In recent years, several potent HDAC inhibitors (HDACi) have been tested in the clinic as anti-cancer agents. In the current study, we have investigated a number of HDACi, including some new, highly-potent compounds, for their potential to induce EBV lytic phase gene expression and to kill EBV-infected cells in combination with anti-herpesviral drugs. Our study included short-chain fatty acids (sodium butyrate and valproic acid); hydroxamic acids [Oxamflatin, Scriptaid, Suberoyl anilide hydroxamic acid (SAHA), Panobinostat (LBH589) and Belinostat (PXD101)]; the benzamide MS275; cyclic tetrapeptide Apicidin, and newly-identified HDAC inhibitor Largazole, which was originally isolated from a marine cyanobacterium. We assayed the induction of lytic phase in EBV-positive lymphoma cell lines exposed to different HDACi for 24–48 hrs, then quantitated the expression of EBV TK and other EBV transcripts by RT-PCR analysis. To determine tumor cytotoxic activity of the combination of HDACi and GCV, EBV+ lymphoma cells were exposed to a range of concentrations of HDACi and GCV for 3 days and then to GCV alone for another 3 days. Efficacy of a particular HDACi in the combination treatment approach was then determined by enumerating living cells. With the exception of SAHA and PXD101, the other HDACi had synergistic activity with anti-viral agents in killing EBV+ lymphoma cells. The hydroxamic acid LBH589, the benzamide MS275, and synthetic largazole derivatives 234a and 234b were 104 to 105-times more potent in killing EBV+ lymphoma cells in presence of GCV, compared to sodium butyrate. The effective concentration of LBH589 was in the range of 50–100 nM, MS275 at 200–500 nM and Largazole 234a and 234b at 100–200 nM. Of note, at these concentrations, the drugs as single agents produced no growth inhibitory activity in the tumor cells. LBH589, MS275 and Largazole 234a and 234b also strongly induced EBV-TK expression in the tumor cells. The effectiveness of these HDACi compounds at such low concentrations makes them potentially applicable as sensitizers to anti-viral therapeutics for the treatment of EBV-associated lymphomas. Our finding therefore provides an intriguing possibility that these novel HDACi may be used as an alternative therapeutic option, in combination with nucleoside antivirals, for the treatment of EBV-associated tumors. Disclosures: Faller: HemaQuest Pharmaceuticals: Consultancy, Equity Ownership. Perrine:HemaQuest Pharmaceuticals, Inc: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding. Williams:HemaQuest Pharmaceuticals: Consultancy, Equity Ownership. Berenson:HemaQuest Pharmaceuticals, Inc: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties.

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Concomitant Suppression of IKZF1, IRF4 and MYC Contribute to the Anti-Tumor Activity of the BET Inhibitor, Cpi-0610, in Disease Models of Multiple Myeloma

Blood ◽

10.1182/blood.v128.22.3320.3320 ◽

2016 ◽

Vol 128 (22) ◽

pp. 3320-3320 ◽

Cited By ~ 1

Author(s):

Ka Tat Siu ◽

Janani Ramachandran ◽

Andrew J. Yee ◽

Homare Eda ◽

Loredana Santo ◽

...

Keyword(s):

Multiple Myeloma ◽

Board Of Directors ◽

Research Funding ◽

Employment Equity ◽

Advisory Committees ◽

Bet Inhibitor ◽

Bet Inhibitors ◽

Equity Ownership ◽

Anti Tumor Activity

Abstract Inhibition of the bromodomain and extra-terminal (BET) proteins is a promising therapeutic strategy for various hematologic malignancies. Previous studies suggest that BET inhibitors constrain tumor cell proliferation and survival mainly through suppression of MYC transcription and activity. However, suppression of the transcription of additional genes also contributes to the anti-tumor activity of BET inhibitors but is less well understood. Here we investigated the therapeutic potential of CPI-0610, a novel BET inhibitor that is currently in a phase I clinical trial in relapsed multiple myeloma (MM) (ClinicalTrials.gov Identifier: NCT02157636). CPI-0610 displays potent in vitro cytotoxicity against MM cell lines and patient-derived MM cells by inducing G1 cell cycle arrest and caspase-dependent apoptosis. Furthermore, CPI-0610-mediated BET inhibition overcomes the protective effects conferred by cytokines and bone marrow stromal cells. We also confirmed the in vivo efficacy of CPI-0610 in a MM xenograft mouse model. CPI-0610 significantly delayed tumor growth and increased the survival of MM-bearing SCID mice. Our study found IKZF1 and IRF4 to be among the primary targets of CPI-0610, along with MYC. These findings indicate that BET inhibition not only results in a robust reduction of MYC transcription and activity but also suppresses the expression of IKZF1 and IRF4 in MM. Given that immunomodulatory drugs stabilize cereblon and facilitate Ikaros degradation in MM cells, we combined it with CPI-0610. Combination studies of CPI-0610 with lenalidomide or pomalidomide show in vitro synergism, in part due to concomitant suppression of IKZF1, IRF4, and MYC, providing a rationale for clinical testing of this drug combination in MM patients. Disclosures Mertz: Constellation Pharmaceuticals, Inc.: Employment, Equity Ownership. Sims:Constellation Pharmaceuticals, Inc.: Employment, Equity Ownership. Cooper:Constellation Pharmaceuticals, Inc.: Employment, Equity Ownership. Raje:Amgen: 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; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Merck: Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Roche: Consultancy, Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Research Funding; Eli Lilly: Research Funding.

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