Synergistic Anti-Tumor Effect of KPT-8602, a Second Generation Selective Inhibitor of Nuclear Export (SINE) Compound, and Panobinostat, a Pan-Histone Deacetylase (HDAC) Inhibitor in Multiple Myeloma

Abstract Background: XPO1 (Exportin-1/CRM1) is the non-redundant nuclear exporter of over 200 cargos including the major tumor suppressor proteins. Deregulated nuclear export by changes in XPO1 expression is a common characteristic for a broad range of cancers and may aid in the evasion of anti-neoplastic mechanisms. As a result, inhibition of XPO1 has emerged as a promising area of cancer treatment. The Selective Inhibitor of Nuclear Export (SINE) compounds, selinexor, as well as a second generation, KPT-8602, bind to the XPO1 cargo binding pocket and disrupt XPO1-mediated nuclear export, resulting in cancer specific cell death. Although selinexor has been evaluated in >1,500 patients and has manageable tolerability, KPT-8602 may have improved tolerability and efficacy based on decreased brain penetration in animal models allowing more frequent dosing. Currently, the safety, tolerability and efficacy of KPT-8602 is being evaluated in a phase 1 trial of patients with relapsed/refractory multiple myeloma (MM; NCT02649790). Since selinexor synergizes with a broad array of anti-MM agents in patients, KPT-8602 is an excellent candidate for combination therapies. In this study, we investigated the use and mechanism of combining KPT-8602 with the pan-histone deacetylase (HDAC) inhibitor, panobinostat, in MM cell lines and in a xenograft mouse model of MM. Methods : MM.1S cells were treated with single agent KPT-8602, panobinostat or a combination of both. The effects of KPT-8602 and/or panobinostat on cell viability were examined using standard viability assays after 72 hours of treatment. Total RNA or protein levels were examined after 24 hours using quantitative PCR or immunoblots, respectively. Immune compromised mice were injected subcutaneously with MM.1S cells. Tumors were allowed to grow to ~150 mm3before treatment. The mice were treated with vehicle, sub-therapeutic doses of KPT-8602 (5 mg/kg PO QDx5) or panobinostat (5 mg/kg IP QDx5) alone or in combination. Tumor growth and animal weights was monitored to determine tumor growth inhibition (TGI), tumor regression, and tolerability to treatment. The tumors were then harvested for immunohistochemical (IHC) analysis. Results : The combination of KPT-8602 and panobinostat was highly effective against MM.1S cell viability. A synergistic anti-cancer effect was observed against MM.1S cells grown in culture and in mice. In cells, the MTT IC50of KPT-8602 was shifted from 50 to 23 nM by the addition of sub cytotoxic concentrations of panobinostat. In mice, single agent treatment with KPT-8602 led to 96.5% tumor growth inhibition whereas panobinostat resulted in 69.4% tumor growth inhibition within 22 days. Remarkably, in the combination of KPT-8602 and panobinostat, 3 out of 8 tumors totally disappeared and the overall tumor regression was 95%, (Figure 1). Both drugs, as single agents and in combination were well tolerated and no significant changes in weight were observed. Gene and protein expression studies revealed that although both compounds target independent proteins (e.g. HDACs or XPO1), the combination significantly enhances markers of cell death (cleavage of PARP-1, caspase-3, etc.). Curiously, KPT-8602 enhances the inhibitory effect panobinostat has on deacetylation as evidenced by histone acetylation. Moreover, DNA damage, as indicated by ϒ-H2AX, significantly increases in the presence of both compounds. Conclusion : KPT-8602 and panobinostat are dissimilar drugs with unique mechanisms of action, and individually affect a broad range of cellular processes. Here we show that the combination of these drugs can dramatically increase the already potent anti-cancer properties of these compounds in MM cell lines. In addition, KPT-8602 enhances the inhibitory effect exerted by panobinostat on histone deacetylation, which coincides with an increase induction of DNA damage. It should be noted that both panobinostat and SINE compounds have been shown to downregulate checkpoint and DNA damage response (DDR) proteins (e.g. RAD51 and Chk1). We hypothesize that the combination of KPT-8602 and panobinostat promotes significant chromatin remodeling in the presence of a compromised DDR pathway, which destabilizes genomic integrity in MM cells and leads to a synergistic effect on cell viability. Together, these data provide rational support for the study of KPT-8602 and panobinostat in clinical trials. Figure 1 Figure 1. Disclosures Argueta: Karyopharm Therapeutics: Employment, Equity Ownership. Chang:Karyopharm Therapeutics: Employment, Equity Ownership. Kashyap:Karyopharm Therapeutics: Employment, Equity Ownership. Elloul:Rubius Therapeutics: Employment. Friedlander:Karyopharm Therapeutics: Employment. Lee:Karyopharm Therapeutics: Employment, Equity Ownership. Kauffman:Karyopharm Therapeutics Inc: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Shacham:Karyopharm Therapeutics: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Senapedis:Karyopharm Therapeutics: Employment, Equity Ownership. Baloglu:Karyopharm Therapeutics: Employment, Equity Ownership.

Download Full-text

Highly Differentiated Anti-CD47 Antibody, AO-176, Potently Inhibits Hematologic Malignancies Alone and in Combination

Blood ◽

10.1182/blood-2019-126298 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 1844-1844

Author(s):

John Richards ◽

Myriam N Bouchlaka ◽

Robyn J Puro ◽

Ben J Capoccia ◽

Ronald R Hiebsch ◽

...

Keyword(s):

Multiple Myeloma ◽

Combination Therapy ◽

Tumor Growth ◽

Growth Inhibition ◽

Tumor Cells ◽

Tumor Growth Inhibition ◽

Employment Equity ◽

Equity Ownership

AO-176 is a highly differentiated, humanized anti-CD47 IgG2 antibody that is unique among agents in this class of checkpoint inhibitors. AO-176 works by blocking the "don't eat me" signal, the standard mechanism of anti-CD47 antibodies, but also by directly killing tumor cells. Importantly, AO-176 binds preferentially to tumor cells, compared to normal cells, and binds even more potently to tumors in their acidic microenvironment (low pH). Hematological neoplasms are the fourth most frequently diagnosed cancers in both men and women and account for approximately 10% of all cancers. Here we describe AO-176, a highly differentiated anti-CD47 antibody that potently targets hematologic cancers in vitro and in vivo. As a single agent, AO-176 not only promotes phagocytosis (15-45%, EC50 = 0.33-4.1 µg/ml) of hematologic tumor cell lines (acute myeloid leukemia, non-Hodgkin's lymphoma, multiple myeloma, and T cell leukemia) but also directly targets and kills tumor cells (18-46% Annexin V positivity, EC50 = 0.63-10 µg/ml) in a non-ADCC manner. In combination with agents targeting CD20 (rituximab) or CD38 (daratumumab), AO-176 mediates enhanced phagocytosis of lymphoma and multiple myeloma cell lines, respectively. In vivo, AO-176 mediates potent monotherapy tumor growth inhibition of hematologic tumors including Raji B cell lymphoma and RPMI-8226 multiple myeloma xenograft models in a dose-dependent manner. Concomitant with tumor growth inhibition, immune cell infiltrates were observed with elevated numbers of macrophage and dendritic cells, along with increased pro-inflammatory cytokine levels in AO-176 treated animals. When combined with bortezomib, AO-176 was able to elicit complete tumor regression (100% CR in 10/10 animals treated with either 10 or 25 mg/kg AO-176 + 1 mg/kg bortezomib) with no detectable tumor out to 100 days at study termination. Overall survival was also greatly improved following combination therapy compared to animals treated with bortezomib or AO-176 alone. These data show that AO-176 exhibits promising monotherapy and combination therapy activity, both in vitro and in vivo, against hematologic cancers. These findings also add to the previously reported anti-tumor efficacy exhibited by AO-176 in solid tumor xenografts representing ovarian, gastric and breast cancer. With AO-176's highly differentiated MOA and binding characteristics, it may have the potential to improve upon the safety and efficacy profiles relative to other agents in this class. AO-176 is currently being evaluated in a Phase 1 clinical trial (NCT03834948) for the treatment of patients with select solid tumors. Disclosures Richards: Arch Oncology Inc.: Employment, Equity Ownership, Other: Salary. Bouchlaka:Arch Oncology Inc.: Consultancy, Equity Ownership. Puro:Arch Oncology Inc.: Employment, Equity Ownership. Capoccia:Arch Oncology Inc.: Employment, Equity Ownership. Hiebsch:Arch Oncology Inc.: Employment, Equity Ownership. Donio:Arch Oncology Inc.: Employment, Equity Ownership. Wilson:Arch Oncology Inc.: Employment, Equity Ownership. Chakraborty:Arch Oncology Inc.: Employment, Equity Ownership. Sung:Arch Oncology Inc.: Employment, Equity Ownership. Pereira:Arch Oncology Inc.: Employment, Equity Ownership.

Download Full-text

First Selective KIT D816V Inhibitor for Patients with Systemic Mastocytosis

Blood ◽

10.1182/blood.v124.21.3217.3217 ◽

2014 ◽

Vol 124 (21) ◽

pp. 3217-3217 ◽

Cited By ~ 7

Author(s):

Erica K. Evans ◽

Brian L. Hodous ◽

Alexandra Gardino ◽

Julia Zhu ◽

Adam Shutes ◽

...

Keyword(s):

Mast Cells ◽

Tumor Growth ◽

Growth Inhibition ◽

Systemic Mastocytosis ◽

Tumor Growth Inhibition ◽

Employment Equity ◽

Equity Ownership ◽

Kit D816v

Abstract Systemic mastocytosis is a disease characterized by the abnormal proliferation and accumulation of mast cells. In aggressive cases, these mast cells accumulate in organs such as bone marrow, liver and spleen and result in compromised organ function with average patient survival only 3 to 5 years after diagnosis. The mast cells of nearly all systemic mastocytosis patients harbor a heterozygous D816V mutation in the activation loop of KIT conferring constitutive, ligand-independent activation of this receptor tyrosine kinase, suggesting this mutation is a driver of disease. While KIT D816V can be targeted by small molecules such as dasatinib and midostaurin, these agents have activity against many human kinases resulting in dose limiting toxicities in the clinic that prevent complete suppression of KIT D816V activity in vivo. In vitro, their potent activity against multiple kinases leads to uncertainties regarding their mechanism of action. Thus far, selective inhibition of the KIT D816V mutation has not been achieved. However starting with a novel chemical library optimized for kinase selectivity, we have identified BLU-285, a small molecule inhibitor targeting KIT exon 17 mutants including the activated KIT D816V kinase. BLU-285 potently disrupts KIT D816V oncogenic signaling as measured by inhibition of both KIT D816V autophosphorylation and phosphorylation of the downstream substrates Akt and Stat3 in the human mast cell leukemia cell line HMC1.2. In vitro, BLU-285 inhibits proliferation and induces apoptosis in the mouse mastocytoma cell line P815. In vivo, BLU-285 is a well-tolerated, orally bioavailable agent that achieves dose dependent tumor growth inhibition in a P815 mouse xenograft model with tumor regression observed at 30 mg/kg once daily dosing. Tumor growth inhibition correlates with inhibition of KIT autophosphorylation; greater than 80% target suppression throughout the 24-hour dosing period is required for effective tumor growth inhibition. Prolonged target suppression is achievable with BLU-285 but not dasatinib, even when dosed at the MTD in mouse. Furthermore, to more closely mimic the nature of systemic mastocytosis, we have developed a disseminated model of disease whereby the in vivo growth of P815-luciferase expressing cells inoculated intravenously can be measured by whole body bioluminescence. Treatment of mice with systemic disease leads to dose dependent inhibition of disease, with a 3-fold increase in survival time when dosed 30 mg/kg QD. In addition, as anticipated by its selectivity profile, BLU-285 is very well tolerated in vivo with no impact on body weight at efficacious doses. Our data demonstrate that selective inhibition of KIT D816V with BLU-285 achieves complete and prolonged inactivation of the disease-driving kinase and suggests that BLU-285 may provide a compelling new therapy for patients with systemic mastocytosis. Disclosures Evans: Blueprint Medicines: Employment, Equity Ownership. Hodous:Blueprint Medicines: Employment, Equity Ownership. Gardino:Blueprint Medicines: Employment, Equity Ownership. Zhu:Blueprint Medicines: Employment, Equity Ownership. Shutes:Blueprint Medicines: Employment, Equity Ownership. Davis:Blueprint Medicines: Employment, Equity Ownership. Kim:Blueprint Medicines: Employment, Equity Ownership. Wilson:Blueprint Medicines: Employment, Equity Ownership. Wilson:Blueprint Medicines: Employment, Equity Ownership. Zhang:Blueprint Medicines: Employment, Equity Ownership. Kohl:Blueprint Medicines: Employment, Equity Ownership. Guzi:Blueprint Medicines: Employment, Equity Ownership. Lengauer:Blueprint Medicines: Employment, Equity Ownership.

Download Full-text

A novel PLK1 inhibitor onvansertib effectively sensitizes MYC-driven medulloblastoma to radiotherapy

Neuro-Oncology ◽

10.1093/neuonc/noab207 ◽

2021 ◽

Author(s):

Dong Wang ◽

Bethany Veo ◽

Angela Pierce ◽

Susan Fosmire ◽

Krishna Madhavan ◽

...

Keyword(s):

Cell Cycle ◽

Dna Damage ◽

Tumor Growth ◽

Radiation Treatment ◽

Tumor Regression ◽

Tumor Growth Inhibition ◽

Cell Cycle Distribution ◽

Cell Renewal ◽

Group 3

Abstract Background Group 3 medulloblastoma (MB) is often accompanied by MYC amplification. PLK1 is an oncogenic kinase that controls cell cycle and proliferation and has been preclinically validated as a cancer therapeutic target. Onvansertib (PCM-075) is a novel, orally available PLK1 inhibitor, which shows tumor growth inhibition in various types of cancer. We aim to explore the effect of onvansertib on MYC-driven medulloblastoma as a monotherapy or in combination with radiation. Methods Crisper-Cas9 screen was used to discover essential genes for MB tumor growth. Microarray and immunohistochemistry on pediatric patient samples were performed to examine the expression of PLK1. The effect of onvansertib in vitro was measure by cell viability, colony-forming assays, extreme limiting dilution assay and RNA-Seq. ALDH activity, cell-cycle distribution and apoptosis were analyzed by flow cytometry. DNA damage was assessed by immunofluorescence staining. Medulloblastoma xenografts were generated to explore the monotherapy or radio-sensitizing effect. Results PLK1 is overexpressed in Group 3 MB. The IC50 concentrations of onvansertib in Group 3 MB cell lines were in a low nanomolar range. Onvansertib reduced colony formation, cell proliferation, stem cell renewal and induced G2/M arrest in vitro. Moreover, onvansertib in combination with radiation increased DNA damage and apoptosis compare with radiation treatment alone. The combination radiotherapy resulted in marked tumor regression in xenografts. Conclusions These findings demonstrate the efficacy of a novel PLK1 inhibitor onvansertib in vitro and in xenografts of Group 3 MB, which suggests onvansertib is an effective strategy as monotherapy or in combination with radiotherapy in MB.

Download Full-text

A Phase 1/2 Study of the Second Generation Selective Inhibitor of Nuclear Export (SINE) Compound, KPT-8602, in Patients with Relapsed Refractory Multiple Myeloma

Blood ◽

10.1182/blood.v128.22.4509.4509 ◽

2016 ◽

Vol 128 (22) ◽

pp. 4509-4509 ◽

Cited By ~ 4

Author(s):

R. Frank Cornell ◽

Adriana C Rossi ◽

Rachid Baz ◽

Craig C Hofmeister ◽

Chaim Shustik ◽

...

Keyword(s):

Clinical Trial ◽

Board Of Directors ◽

Nuclear Export ◽

Research Funding ◽

Low Dose ◽

Phase 1 ◽

Single Agent ◽

Employment Equity ◽

Advisory Committees ◽

Equity Ownership

Abstract Introduction - Inhibition of Exportin 1 (XPO1) is a novel treatment approach for multiple myeloma (MM). XPO1 mediates the nuclear export of cell-cycle regulators and tumor suppressor proteins leading to their functional inactivation. In addition, XPO1 promotes the export and translation of the mRNA of key oncoproteins (e.g. c-MYC, BCL-2, Cyclin D). XPO1 overexpression occurs in solid and hematological malignancies, including MM and is essential for MM cell survival. Selinexor, the first oral SINE compound, has shown promising anti-MM activity in phase 1 studies but has been associated with gastrointestinal and constitutional toxicities including nausea, anorexia and fatigue. KPT-8602 is a second generation oral SINE compound with similar in vitro potency to selinexor, however, has substantially reduced brain penetration compared with selinexor, and demonstrated markedly improved tolerability with minimal anorexia and weight loss in preclinical toxicology studies. In murine models of MM, KPT-8602 can be dosed daily (QDx5) with minimal anorexia and weight loss. We have therefore initiated a phase 1/2 first-in-human clinical trial. Methods - This phase 1/2 clinical trial was designed to evaluate KPT-8602 as a single agent and in combination with low dose dexamethasone (dex) in patients (pts) with relapsed / refractory MM (RRMM). KPT-8602 is dosed orally (QDx5) for a 28-day cycle with a starting dose of 5 mg. Low dose dex (20 mg, twice weekly) is allowed after cycle 1 if at least a minimal response (MR) is not observed. The primary objective is to evaluate the safety and tolerability including dose-limiting toxicity (DLT), determine the maximum tolerated dose (MTD), the recommended Phase 2 dose (RP2D), and evidence for anti-MM activity for KPT-8602 single agent and in combination with dex. The pharmacokinetic (PK) and pharmacodynamic (PDn; XPO1 mRNA) profile of KPT-8602 will also be determined. PDn predictive biomarker analysis and ex vivo drug response assays are underway using tumor cells from bone marrow aspirates before treatment, during and at relapse. These analyses include cell death pathway assays by flow and nuclear/cytoplasmic localization of XPO1, NF-ƙB, IƙBα, IKKα, NRIF and p53 by imaging flow and IHC. Results - As of 01-Aug-2016, 6 pts 2 M/4 F, (median of 6 prior treatment regimens, median age of 71) with RRMM have been enrolled. Common related grade 1/2 adverse events (AEs) include thrombocytopenia (3 pts), nausea (2 pts) and diarrhea (2 pts). Grade 3 AEs include neutropenia (1 pt) and dehydration (1 pt). No grade 4 or 5 AEs have been reported. No DLTs have been observed and the MTD has not been reached. 5 pts were evaluable for responses (1 pt pending evaluation): 1 partial response, 1 minimal response, and 3 stable disease; no pts have progressed on therapy with the longest on for >5 months. The PK properties following oral administration showed that 5 mg of KPT-8602 was rapidly absorbed (mean tmax= 1 hr, mean Cmax= 30.6 ng/mL). The mean AUCinf was calculated to be 141 ng•hr/mL. After tmax, KPT-8602 declined at an estimated mean t½ of 4 hr. At the same dose level, XPO1 mRNA expression was the highest (~2.5 fold) at 8 hr post dose. Conclusions - Oral KPT-8602 is well tolerated in heavily pretreated pts with RRMM. Gastrointestinal and constitutional toxicities observed with twice weekly selinexor have not been observed with 5x/week KPT-8602, including in pts on study for >4 months. PK was predictable and in line with selinexor. These early results show encouraging disease control with pts remaining on therapy. Enrollment is on-going. Disclosures Rossi: Takeda: Speakers Bureau; Janssen: Speakers Bureau; Onyx: Research Funding, Speakers Bureau; Celgene: Consultancy, Speakers Bureau. Baz:Takeda/Millennium: Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Karyopharm: Research Funding; Signal Genetics: Research Funding; Bristol-Myers Squibb: Research Funding; Merck: Research Funding; Novartis: Research Funding. Hofmeister:Karyopharm Therapeutics: Research Funding; Arno Therapeutics, Inc.: Research Funding; Signal Genetics, Inc.: Membership on an entity's Board of Directors or advisory committees; Janssen: Pharmaceutical Companies of Johnson & Johnson: Research Funding; Incyte, Corp: Membership on an entity's Board of Directors or advisory committees; Celgene: Research Funding; Takeda Pharmaceutical Company: Research Funding; Teva: Membership on an entity's Board of Directors or advisory committees. Shustik:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Millenium: 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; Amgen: 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. Richter:Amgen: Consultancy, Speakers Bureau; Takeda: Consultancy, Speakers Bureau; Celgene: Consultancy, Speakers Bureau; Jannsen: Speakers Bureau. Chen:Janssen: Honoraria, Research Funding; Takeda: Research Funding; Celgene: Honoraria, Research Funding. Vogl:Takeda: Consultancy, Research Funding; Celgene: Consultancy; GSK: Research Funding; Calithera: Research Funding; Teva: Consultancy; Karyopharm: Consultancy; Acetylon: Research Funding; Constellation: Research Funding. Shacham:Karyopharm Therapeutics: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Baloglu:Karyopharm Therapeutics: Employment, Equity Ownership. Senapedis:Karyopharm Therapeutics: Employment, Equity Ownership. Ellis:Karyopharm Therapeutics: Employment, Equity Ownership. Friedlander:Karyopharm Therapeutics: Employment. Choe-Juliak:Karyopharm Therapeutics: Employment. Sullivan:Karyopharm Therapeutics: Research Funding. Kauffman:Karyopharm Therapeutics Inc: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees.

Download Full-text

Eltanexor (KPT-8602), a Second-Generation Selective Inhibitor of Nuclear Export (SINE) Compound, in Patients with Higher-Risk Myelodysplastic Syndrome

Blood ◽

10.1182/blood-2019-124136 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 2997-2997

Author(s):

Sangmin Lee ◽

Bhavana Bhatnagar ◽

Sanjay R Mohan ◽

William T. Senapedis ◽

Erkan Baloglu ◽

...

Keyword(s):

Nuclear Export ◽

Progressive Disease ◽

Overall Response Rate ◽

Response Rate ◽

Single Agent ◽

Research Support ◽

Employment Equity ◽

Advisory Committees ◽

Equity Ownership ◽

Anti Tumor Activity

Background: Overexpression of exportin 1 (XPO1) in malignant cells increases the nuclear export/inactivation of tumor suppressor proteins (e.g. p53, IκB), and promotes the translation of eIF4E-bound mRNAs coding oncoproteins (e.g. c-MYC, BCL-2, AR). Selinexor plus low dose dexamethasone (Sel-dex) was recently approved in the United States based on data from the STORM study, wherein Sel-dex induced an overall response rate (ORR) of 26.2% in patients with penta-exposed, triple-class refractory multiple myeloma. Eltanexor (elta), a second-generation SINE compound, has demonstrated reduced brain penetration and improved tolerability compared to selinexor in non-clinical animal models, and preliminary anti-tumor activity in clinical trials of hematologic and solid tumor malignancies. The primary objective of this study was to assess the safety, tolerability and anti-tumor activity of elta in patients (pts) with higher risk (HR)-Myelodysplastic Syndrome (MDS). Methods: This is part of a Phase 1/2 study (NCT02649790) to determine the safety, tolerability and anti-tumor activity of elta in advance malignancies. This trial planned to evaluate single agent activity of elta in an expansion cohort of 20 pts with HR-MDS (intermediate-2 [Int-2] or high-risk by the International Prognostic Scoring System [IPSS]). Other key eligibility criteria included: age ≥18, ECOG ≥1, adequate organ function, and documented evidence of progressive disease as defined by the 2006 International Working Group (IWG) Response Criteria for MDS, which includes hypomethylating agent (HMA) failure. The dose levels evaluated in the MDS cohort were 10 and 20 mg elta taken orally once daily for 5 consecutive days per week in a 28-day cycle. A key efficacy endpoint is overall response rate (ORR) which includes complete response (CR), partial response (PR), marrow CR (mCR), and hematologic improvement (HI) using the 2006 IWG Response Criteria for MDS. Results: Twenty pts (median age 77 years-old; range 62-89; 55% male) were enrolled as of 15 July 2018 (n=15 at 20 mg and n=5 at 10 mg). All pts were refractory to HMA with a median of 2 prior therapies (range 1 - 5) and 90% high risk via IPSS (11 pts high, 7 pts Int-2, 2 pts Int-1 [IPSS-R high]). Fourteen of 20 pts were evaluable for response, 2 are pending disease reassessment and 4 were not evaluable (NE). Preliminary efficacy demonstrated best responses of 4 mCR (29%) and 6 stable disease (SD; 43%) and 4 progressive disease (PD; 29%). The disease control rate (mCR + SD) was 71%. The median time on treatment for all pts was 69 days (range 5+ - 379) with a median time on study of 115 days (range 5+ - 400). The most frequent (≥3 pts) treatment-related adverse events (TRAEs) any grade (Gr) included nausea (53%), decreased appetite (33%), diarrhea (27%), thrombocytopenia, anemia, neutropenia, vomiting and dysgeusia (20% each). The most frequent Gr≥3 TRAEs included thrombocytopenia and anemia which are expected in this immune compromised patient population. All AEs were reversible and manageable by supportive care and dose modification. The 4 pts NE for response were pts who discontinued from treatment before having the first disease response reassessment due to: Gr3 diarrhea related to eltanexor, Gr5 sepsis not related per investigator, Gr3 pneumonia not related, and withdrawal by pt. Conclusion: Oral eltanexor demonstrated preliminary anti-tumor activity as a single agent in elderly pts with HMA-refractory HR-MDS, including mCRs or disease stabilization, and a manageable tolerability profile. Further evaluation of efficacy and safety in HR-MDS is on-going. Disclosures Lee: Helsinn: Consultancy; Jazz Pharmaceuticals, Inc: Consultancy; Roche Molecular Systems: Consultancy; AstraZeneca Pharmaceuticals: Consultancy; Karyopharm Therapeutics: Consultancy; Ai Therapeutics: Research Funding. Bhatnagar:Karyopharm Therapeutics: Other: Research support; Novartis and Astellas: Consultancy, Honoraria; Cell Therapeutics, Inc.: Other: Research support. Senapedis:Karyopharm Therapeutics Inc: Employment, Equity Ownership, Patents & Royalties. Baloglu:Karyopharm Therapeutics Inc: Equity Ownership, Patents & Royalties; resTORbio: Employment. Wang:Karyopharm Therapeutics Inc: Employment. Shah:Karyopharm Therapeutics Inc: Employment, Equity Ownership. 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.

Download Full-text

Glutaminase Inhibitor CB-839 Synergizes with Pomalidomide in Preclinical Multiple Myeloma Models

Blood ◽

10.1182/blood.v124.21.4720.4720 ◽

2014 ◽

Vol 124 (21) ◽

pp. 4720-4720 ◽

Cited By ~ 3

Author(s):

Francesco Parlati ◽

Mathew Gross ◽

Julie Janes ◽

Evan Lewis ◽

Andy MacKinnon ◽

...

Keyword(s):

Multiple Myeloma ◽

Clinical Trials ◽

Growth Inhibition ◽

Tumor Cells ◽

Single Agent ◽

Aspartate Transcarbamylase ◽

Employment Equity ◽

Two Agents ◽

Equity Ownership ◽

Hematological Tumor

Abstract Many hematological tumor cells are dependent on glutamine for growth and survival. Glutamine is the most abundant amino acid in plasma and can be utilized by tumor cells for production of energy and generation of building blocks for the synthesis of macromolecules. Small molecule CB-839 inhibits glutaminase (GLS) activity thereby blocking cellular glutamine utilization resulting in an anti-tumor effect in several hematological tumor types including multiple myeloma (MM), acute lymphocytic leukemia, and several types of non-Hodgkin’s lymphoma [Parlati et al. Blood 2013 122:4226]. Phase 1 clinical trials have been initiated to test the safety, pharmacokinetics, pharmacodynamics, and clinical activity of single agent CB-839 in several hematological malignancies. In anticipation of potential combinations of CB-839 with standard of care agents in future MM clinical trials, we tested the effects of CB-839 in combination with the IMiD, pomalidomide (POM). POM caused complete growth inhibition in MM.1S cells with an EC50 of 16 nM as opposed to partial growth inhibition in RPMI8226 cells, with an EC50 of 130 nM. CB-839 caused complete growth inhibition in MM.1S cells with an EC50 value of 26 nM and produced a cytotoxic effect in RPMI8226 cells with an EC50 of 160 nM. When combined, CB-839 enhanced the anti-proliferative activity of POM in both POM-sensitive MM.1S and POM-resistant RPMI8226 cells resulting in a synergistic anti-tumor effect as demonstrated by combination index values between 0.18-0.62 (mean= 0.36) for the MM.1S and 0.25-0.72 (mean= 0.38) for the RPMI8226 cells. To investigate the mechanism that underlies the observed synergy, RPMI8226 cells were treated for 24 hours and changes in proteins and metabolites were measured by reverse-phase-protein array and LC/MS, respectively. When treated with CB-839 alone, RPMI8226 cells respond by decreasing mTOR pathway signaling proteins (e.g. phospho-mTOR, phospho-p70S6K, phospho-PRAS40, phospho-S6), decreasing the amount of oncogenic proteins (c-Myc and c-Kit), and increasing programmed cell death pathway proteins (e.g. cleaved caspase 7, cleaved PARP), consistent with the cytotoxic activity observed for CB-839. Several of these changes were further enhanced in the presence of POM (e.g. phospho-p70S6K, phospho-S6, phospho-PRAS40, c-kit, c-Myc), however only the enhanced decrease in c-Myc reached statistical significance. Metabolite analysis showed changes with CB-839 consistent with GLS inhibition (e.g. decreases in glutamate, aspartate, succinate and malate and increases in glutamine). On the other hand, single agent POM caused very modest changes in the metabolite profile. When the two agents were combined, metabolite levels were consistent with those observed with single agent CB-839, with the notable exception of carbamoyl-aspartate where lower levels were measured in the combination group in comparison to cells treated with either agent alone. Carbamoyl-aspartate is an intermediate in the pyrimidine biosynthesis pathway and is synthesized by the multi-catalytic enzyme CAD (carbamoyl-phosphate synthetase 2, aspartate transcarbamylase, dihydroorotase), an enzyme that is regulated by mTOR [Ben-Sahra et al. (2013) Science339: 1323-8]. These observations suggest that CB-839 dampens mTOR signaling and POM may further attenuate this response, possibly contributing to the synergistic anti-tumor effect. These data motivated testing the anti-tumor effect of the combination of CB-839 and POM in mice bearing RPMI8226 xenografts. Oral dosing with single agent CB-839 and POM resulted in tumor growth inhibition (TGI) of 64% and 46%, respectively, whereas the combination of the two agents resulted in a TGI of 97%. Efficacious doses of CB-839 and POM alone or in combination were well tolerated with no effect on animal body weight. These promising results indicate that GLS inhibition with CB-839 in combination with POM may provide therapeutic benefit in MM and provide motivation for future clinical studies. Disclosures Parlati: Calithera Biosciences: Employment, Equity Ownership. Gross:Calithera Biosciences: Employment, Equity Ownership. Janes:Calithera Biosciences: Employment, Equity Ownership. Lewis:Calithera Biosciences: Employment, Equity Ownership. MacKinnon:Calithera Biosciences: Employment, Equity Ownership. Rodriguez:Calithera Biosciences: Employment, Equity Ownership. Shwonek:Calithera Biosciences: Employment, Equity Ownership. Bennett:Calithera Biosciences: Employment, Equity Ownership.

Download Full-text

Alvocidib Potentiates the Activity of Venetoclax in Preclinical Models of Acute Myeloid Leukemia

Blood ◽

10.1182/blood.v128.22.1652.1652 ◽

2016 ◽

Vol 128 (22) ◽

pp. 1652-1652

Author(s):

Clifford J. Whatcott ◽

James M Bogenberger ◽

Wontak Kim ◽

Hillary Haws ◽

Nanna Hansen ◽

...

Keyword(s):

Clinical Trials ◽

Cell Viability ◽

Cell Lines ◽

Research Funding ◽

Single Agent ◽

Employment Equity ◽

Fold Reduction ◽

Remission Rates ◽

Equity Ownership

Abstract Introduction Venetoclax (ABT-199) is an approved BCL-2 inhibitor for the treatment of patients with chronic lymphocytic leukemia (CLL). Multiple clinical trials are underway to explore its efficacy in additional indications. While venetoclax demonstrated high remission rates in combination with azacitidine in early stage clinical trials, the question of durability of responses and primary and acquired resistance remain, especially given the modest activity and rapid development of resistance as a single agent. One reported mechanism of intrinsic resistance is high expression of other BCL-2 family proteins, including MCL-1. We and others have demonstrated that the CDK9 inhibitor, alvocidib, can mediate transcriptional repression of anti-apoptotic MCL-1. It has also been shown that alvocidib can increase pro-apoptotic BIM, a dual activator and sensitizer BH3-only protein that can directly induce apoptosis and simultaneously inactivate anti-apoptotic BCL-2 family proteins such as MCL-1 and BCL-2, thus having the same effect on mitochondria-associated apoptosis as MCL-1 down-regulation, with the potential to directly induce apoptosis. An alvocidib-containing cytotoxic chemotherapy regimen demonstrated favorable remission rates in high-risk AML patients over standard therapy in a randomized Phase 2 trial indicating its potential role and safety in AML. We hypothesized that alvocidib and venetoclax would synergize against AML cells by shifting the overall balance of pro- and anti-apoptotic BCL-2 proteins in favor of apoptosis and thus represent a novel active treatment regimen in AML. Aims This study seeks to examine the efficacy of a treatment regimen containing alvocidib and venetoclax in multiple preclinical studies, including in vivo models of AML. Methods Cell viability assays interrogating alvocidib and venetoclax activity in cell lines were performed using CellTiter-Glo according to manufacturer's protocol. mRNA/miRNA expression changes were assessed using standard RT-PCR technique. Protein expression changes were assessed using standard western immunoblotting technique. To assess the efficacy of an alvocidib and venetoclax combination on tumor growth in an in vivo model, the OCI-AML3 xenograft mouse model and ex vivo studies with AML patient samples were performed. Results Herein we demonstrate that alvocidib inhibits both mRNA and protein expression of MCL-1 in a time and concentration-dependent fashion in 3 out of 4 AML cell lines analyzed, while in cells where alvocidib did not reduce MCL-1 protein levels (i.e. MOLM-13) a dose-dependent decrease in miR17-92, and concomitant increase in BIM protein was observed after 24 hours of alvocidib treatment. The alvocidib-venetoclax combination resulted in very strong synergistic reductions of cell viability (with combination indices [CI] of 0.4 to 0.7), both in venetoclax-sensitive and resistant cells. The venetoclax-sensitive lines, MV4-11 and MOLM-13, exhibited 5- to 10-fold reduction of venetoclax EC50 values in the low nM range when combined with only 80 nM alvocidib. Importantly, venetoclax-resistant lines, OCI-AML3 and THP-1, exhibited at least 20-fold reduction of venetoclax EC50 values from near 1 µM to 10-50 nM, when combined with 80 nM alvocidib.In the venetoclax-resistant OCI-AML3 xenograft model, single agent alvocidib and venetoclax achieved tumor growth inhibition (TGI) of 9.7 and 31.5%, respectively, while the combination achieved 87.9% TGI at the same dose levels of individual drugs. Conclusions Taken together, our data suggest that the combination of alvocidib with venetoclax is highly synergistic in vitro and in vivo, in both venetoclax-sensitive and -resistant AML across a heterogeneous genomic background. The particularly high level of synergy achieved in venetoclax-resistant cell lines highlights the central importance of both BCL-2 and MCL-1-mediated cell survival in AML. Importantly, the addition of alvocidib to venetoclax treatment reduced IC50s to clinically achievable concentrations. Therefore, we conclude that an alvocidib/venetoclax combination may be a novel approach for the treatment of AML and warrants further pre-clinical and clinical validation. Disclosures Whatcott: Tolero Pharmaceuticals: Employment. Kim:Tolero Pharmaceuticals: Employment. Haws:Tolero Pharmaceuticals: Employment. Mesa:Celgene: Research Funding; Galena: Consultancy; Promedior: Research Funding; Ariad: Consultancy; Novartis: Consultancy; CTI: Research Funding; Incyte: Research Funding; Gilead: Research Funding. Peterson:Tolero Pharmaceuticals: Employment. Siddiqui-Jain:Tolero Pharmaceuticals: Employment. Weitman:Tolero Pharmaceuticals: Employment. Bearss:Tolero Pharmaceuticals: Employment, Equity Ownership, Patents & Royalties. Warner:Tolero Pharmaceuticals: Employment, Equity Ownership, Patents & Royalties.

Download Full-text

EZH2 Inhibitors Are Broadly Efficacious in Multiple Myeloma As Single Agent and in Combination with Standard of Care Therapeutics

Blood ◽

10.1182/blood.v128.22.5672.5672 ◽

2016 ◽

Vol 128 (22) ◽

pp. 5672-5672 ◽

Cited By ~ 1

Author(s):

Shilpi Arora ◽

Kaylyn Williamson ◽

Shruti Apte ◽

Srividya Balachander ◽

Jennifer Busby ◽

...

Keyword(s):

Multiple Myeloma ◽

Cell Lines ◽

Single Agent ◽

Standard Of Care ◽

Tumor Growth Inhibition ◽

Sequencing Data ◽

Employment Equity ◽

Chip Sequencing ◽

Equity Ownership

Abstract Post-translational modifications of the histone proteins play a key role in regulating processes that require access to DNA. Specifically, methylation of lysine 27 on histone 3 (H3K27) is intimately linked with transcriptional repression. EZH2, a histone lysine methyl transferase is the catalytic component of the PRC2 complex, which catalyzes H3K27 methylation. EZH2 dysregulation has been observed in different malignancies and inhibition of its catalytic activity has emerged as a novel therapeutic approach to treat human cancers. Potent, selective and reversible EZH2 small molecule inhibitors are currently being tested in Ph. 1 clinical trials. We and others have reported EZH2 dependencies across non-Hodgkin Lymphoma subtypes in cancer cell lines, in xenograft mouse models and in lymphoma patients. We identified Multiple Myeloma as potential clinical application for EZH2 inhibitors. Treatment with EZH2 inhibitors such as CPI-360, CPI-169 and CPI-1205 cause apoptosis in multiple myeloma and plasmacytoma cell models and causes tumor growth inhibition in myeloma xenograft models at well tolerated doses. An EZH2-controlled transcriptional signature across various multiple myeloma was identified using integrated RNA-sequencing and ChIP-sequencing data. Combination studies testing EZH2 inhibitors with standard of care (SOC) agents across a panel of multiple myeloma cell lines showed synergistic responses with several of the SOC agents in vitro and in vivo. Disclosures Arora: Constellation Pharmaceuticals: Employment, Equity Ownership. Williamson:Constellation Pharmaceuticals: Employment, Equity Ownership. Apte:Constellation Pharmaceuticals: Employment, Equity Ownership. Balachander:Constellation Pharmaceuticals: Employment, Equity Ownership. Busby:Constellation Pharmaceuticals: Employment, Equity Ownership. Hatton:Constellation Pharmaceuticals: Employment, Equity Ownership. Bryant:Constellation Pharmaceuticals: Employment, Equity Ownership. Trojer:Constellation Pharmaceuticals: Employment, Equity Ownership.

Download Full-text

EMBR-30. A NOVEL PLK1 INHIBITOR ONVANSERTIB EFFECTIVELY SENSITIZES GROUP 3 MEDULLOBLASTOMA TO RADIOTHERAPY

Neuro-Oncology ◽

10.1093/neuonc/noab090.047 ◽

2021 ◽

Vol 23 (Supplement_1) ◽

pp. i12-i12

Author(s):

Dong Wang ◽

Bethany Veo ◽

Angela Pierce ◽

Susan Foamier ◽

Ilango Balakrishnan ◽

...

Keyword(s):

Cell Cycle ◽

Dna Damage ◽

Tumor Growth ◽

Tumor Regression ◽

Tumor Growth Inhibition ◽

Cell Cycle Distribution ◽

Cell Renewal ◽

Group 3 ◽

Orthotopic Xenografts

Abstract Medulloblastoma (MB) is often accompanied by MYC amplification. PLK1 is an oncogenic kinase that controls cell cycle and proliferation, and it has been preclinically validated as a cancer therapeutic target. Onvansertib (PCM-075) is a novel, orally available PLK1 inhibitor, which shows tumor growth inhibition in many types of cancer. We examined the effect of Onvansertib on MYC-driven medulloblastoma as a monotherapy or in combination with radiation. A Crisper-Cas9 screen was used to discover essential genes for MB tumor growth. Microarray and immunohistochemistry on pediatric patient samples were performed to examine the expression of PLK1. The effect of Onvansertib in vitro was measure by cell viability, colony-forming assays, extreme limiting dilution assay, and RNA-Seq. ALDH activity, cell-cycle distribution, and apoptosis were analyzed by flow cytometry. DNA damage was assessed by immunofluorescence staining. Medulloblastoma xenografts were generated to explore the monotherapy or radio-sensitizing effect. PLK1 is overexpressed in Group 3 MB. The IC50 concentrations of Onvansertib in Group 3 MB cell lines were between 4.9 and 6 nM. Onvansertib reduced colony formation, cell proliferation, stem cell renewal, and induced G2/M arrest in vitro. Moreover, Onvansertib in combination with radiation increased DNA damage and apoptosis compared with radiation alone. The combination of Onvansertib with radiotherapy resulted in marked tumor regression in orthotopic xenografts. These findings suggest that Onvansertib is an effective strategy in combination with radiotherapy in MB.

Download Full-text

Enhanced Activity of GA101, a Novel Type II, Glycoengineered CD20 Antibody, In Combination with Bendamustine or Fludarabine, and with the Bcl-2 Family Inhibitors ABT-737 or ABT-263

Blood ◽

10.1182/blood.v116.21.3915.3915 ◽

2010 ◽

Vol 116 (21) ◽

pp. 3915-3915 ◽

Cited By ~ 1

Author(s):

Frank Herting ◽

Sabine Bader ◽

Pablo Umana ◽

Christian Klein

Keyword(s):

Tumor Growth ◽

Growth Inhibition ◽

Optimal Dose ◽

Tumor Growth Inhibition ◽

Superior Efficacy ◽

Combination Studies ◽

Equity Ownership ◽

Tumor Remission ◽

Complete Tumor

Abstract Abstract 3915 GA101 is type II, glycoengineered CD20 antibody currently in PhII/III clinical trials. GA101 mediates enhanced direct cell death with a concomitant reduction of CDC; and high ADCC induction due to increased affinity for FcgRIIIa. We have shown that GA101 compared to rituximab mediates superior efficacy in NHL xenograft models including the induction of complete tumor remission. In clinical practice the combination of rituximab with chemotherapy e.g. CHOP, CVP, bendamustine, fludarabine or FC results in a substantial clinical benefit. To assess the potential of GA101 for combination with bendamustine or fludarabine, in vivo combination studies in s.c. Z138 (MCL) xenografts in Scid beige mice were devised. GA101 and rituximab at sub-optimal doses of 1 mg/kg (once weekly) were combined with 3 mg/kg bendamustine (days 19, 20, 21, 22); or with 40 mg/kg fludarabine (days 22, 23, 24) and compared to the corresponding monotherapy arms. GA101 in combination with bendamustine mediated statistically superior efficacy in terms of tumor growth inhibition (TGI) compared to the combination of rituximab and bendamustine: TGI values on day 33 were 29% for rituximab, 42% for rituximab + bendamustine, 47% for GA101 and 72% for GA101 + bendamustine. Treatment with bendamustine did not show significant antitumor activity. Statistical evaluation based on sAUC showed a more than additive and significant effect on tumor growth for the combination of GA101 with bendamustine compared to the corresponding monotherapy arms. GA101 in combination with fludarabine demonstrated statistically superior efficacy in terms of TGI and yielded a significant difference compared to the combination of rituximab and fludarabine or GA101 as monotherpy. TGI values on day 36 were 50% for fludarabine, 60% for rituximab, 85% for rituximab + fludarabine, 86% for GA101 and >100% for GA101 + fludarabine. Furthermore, the superiority of the GA101-fludarabine combination was demonstrated by the observation of 3 tumor-free animals at the end of the study. ABT-263 (navitoclax) is a Bcl-2 family inhibitor that is currently in Phase I/II clinical trials for lymphoid malignancies. To provide evidence that GA101 can be combined with ABT-263 and the experimental Bcl-2 family inhibitor ABT-737, in vivo combination studies in s.c. SU-DHL4 (DLBCL) xenografts in Scid beige mice were devised. 10 mg/kg GA101 and rituximab (once weekly) were combined with 50 mg/kg ABT-737 (i.p., days 19, 22, 24, 26, 29, 31, 33). In a second study, 3 mg/kg GA101 or 10 mg/kg rituximab (once weekly) were combined with 100 mg/kg ABT-263 (orally, once daily). GA101 at a sub-optimal dose of 10 mg/kg demonstrated statistically superior efficacy in combination with ABT-737 in terms of tumor growth inhibition compared to GA101 alone or the combination of 10 mg/kg rituximab and ABT-737. Both combination treatments were statistically significant compared to the corresponding monotherapy arms. TGI values based on means on day 36 were 20% for ABT-737, 45% for rituximab, 92% for rituximab + ABT-737, 96% for GA101 and >100% for GA101 + ABT-737. The superiority of the combination of GA101 and ABT-737 was supported by complete tumor regression in all animals whereas none was observed with the combination of rituximab and ABT-737. GA101 at a sub-optimal dose of 3 mg/kg or rituximab at a dose of 10 mg/kg mediated statistically superior efficacy in terms of tumor growth inhibition in combination with ABT-263 compared to the respective monotherapy arms. TGI values based on means on day 43 were 15% for ABT-263, 89% for rituximab, >100% for rituximab + ABT-263, 80% for GA101 (at the sub-optimal dose) and >100% for GA101 (sub-optimal dose) + ABT-263. Taken together i) GA101 as single agent was at least as efficacious as the combination of rituximab with bendamustine, fludarabine or ABT-737; ii) the combination of GA101 with bendamustine or fludarabine was superior to the respective monotherapy arms and resulted in an enhanced, at least additive effect of the combination; iii) the combination of GA101 with Bcl-2 family inhibitors ABT-737 and ABT-263 was superior to the respective monotherapy arms and resulted in an enhanced effect of the combination including the induction of tumor remission. These data strongly support the further clinical investigation of GA101 in combination with Fludarabine, Bendamustine or Bcl-2 family inhibitors. Disclosures: Herting: Roche: Employment. Bader:Roche: Employment. Umana:Roche: Employment, Equity Ownership. Klein:Roche: Employment, Equity Ownership.

Download Full-text