Antagonist Anti-CD40 Monoclonal Antibody, CHIR-12.12, Inhibits Growth of a Rituximab-Resistant NHL Xenograft Model and Achieves Synergistic Activity When Combined with Ineffective Rituximab.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3281-3281 ◽  
Author(s):  
Li Long ◽  
Xia Tong ◽  
Montesa Patawaran ◽  
Lea Aukerman ◽  
Julie Klinger ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Tumor Growth ◽  
B Cell ◽  
Tumor Cells ◽  
Xenograft Model ◽  
Synergistic Activity ◽  
B Cell Malignancies ◽  
Hodgkin's Lymphomas ◽  
Anti Tumor Activity

Abstract CD40 and CD20 are expressed in several B-cell malignancies and represent attractive targets for therapeutic intervention. The anti-CD20 monoclonal antibody, rituximab, is an approved drug for the treatment of non-Hodgkin’s lymphomas. however, the existence of patients with rituximab-resistant disease limits its clinical utility. We have previously reported that the novel, highly potent, fully human antagonistic anti-CD40 monoclonal antibody, CHIR-12.12, generated from XenoMouse® mice (Abgenix, Inc) has greater anti-tumor activity than rituximab in both rituximab-responsive and rituximab-resistant human NHL models. In this study, we evaluated the potential therapeutic application of combining CHIR-12.12 and rituximab for the treatment of NHL. Namalwa is a Burkitt’s lymphoma cell line that gives rise to aggressive rituximab-resistant tumors when implanted in nude mice. Direct treatment of these tumor cells with CHIR-12.12 or rituximab in culture does not affect cell growth when compared to treatment with an isotype control antibody. Although Namalwa cells express more CD20 than CD40 (average of 10,059 CD20 and 3,138 CD40 molecules per cell respectively, P=0.05), when tested for in vitro ADCC killing using human NK cells as effectors, CHIR-12.12 mediated stronger target cell lysis than rituximab (31.43% vs. 14.15%, P<0.0001). Adding CHIR-12.12 and rituximab together did not enhance the in vitro ADCC killing. When CHIR-12.12 and rituximab were tested in a subcutaneous Namalwa xenograft model, CHIR-12.12 alone caused 60% tumor growth inhibition (P=0.028) whereas rituximab alone at 10 and 20 mg/kg did not inhibit Namalwa tumor growth. When tumor-bearing mice were administered rituximab at 10 mg/kg plus CHIR-12.12 at 5 or 10 mg/kg, synergistic anti-tumor activity was observed in a CHIR-12.12 dose-dependent manner. The mean tumor volume reduction in combination groups is 77% with CHIR-12.12 at 5 mg/kg (P=0.0037) and 83% with CHIR-12.12 at 10 mg/kg (P=0.0018), respectively. The potential interaction between CD40 and CD20 molecules was evaluated in vitro by treating the tumor cells with CHIR-12.12 and assessing the change in CD20 expression and vice versa. The result showed no augmentation of one antigen expression by treating the tumor cells with the other antibody. The mechanism of anti-tumor synergy observed in this combination is under evaluation. Taken together, these data suggest that the combination therapy with anti-CD40 CHIR-12.12 and rituximab has the potential to improve patient outcome in B-cell malignancies co-expressing CD20 and CD40 antigens and support the further development of CHIR-12.12 antibody for treatment of B-cell malignancies.

Development of a New Fully Human Anti-CD20 Monoclonal Antibody for the Treatment of B-Cell Malignancies.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2349-2349
Author(s):  
Gadi Gazit Bornstein ◽  
Christophe Queva ◽  
Mohammad Tabrizi ◽  
Anne VanAbbema ◽  
Carlos Chavez ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
B Cell ◽  
Clinical Activity ◽  
Human Antibody ◽  
B Cell Malignancies ◽  
B Lymphoma ◽  
Hodgkin's Lymphomas ◽  
Anti Tumor Activity

Abstract In spite of the widespread use of Rituximab, a chimeric monoclonal antibody with demonstrated efficacy in the treatment of non-Hodgkin’s lymphomas, there is a recognized need to develop fully human antibodies with improved efficacy. Towards this end, using XenoMouse™ technology, a fully human IgG1 monoclonal antibody specific to human CD20 was generated. This antibody, denoted mAb 1.5.3, evoked enhanced pro-apoptotic activity in vitro, as compared to Rituximab, in the Ramos human lymphoma cell line. In addition, mAb 1.5.3 was active in mediating complement dependent cytotoxicity (CDC) and elicited improved antibody-dependent cellular cytotoxicity (ADCC) relative to Rituximab in Ramos, Raji, and Daudi human B-lymphoma lines. To recapitulate various aspects of acquired resistance to Rituximab, as observed in a subpopulation of patients, Rituximab-resistant clones were established from lymphoma lines. Interestingly, mAb 1.5.3 demonstrated superior cytolytic activity against engineered Rituximab-refractory lymphoma clones, as well as across multiple human B-lymphoma and chronic B-cell leukemia lines in an in vitro whole blood assay. Furthermore, mAb 1.5.3 exhibited enhanced anti-tumor activity in Rituximab-sensitive cell lines and -refractory engineered lymphoma clones in vivo. Lastly, mAb 1.5.3 produced a superior B-cell depletion profile in lymph node organs and bone marrow as compared to Rituximab in a primate PD model. In contrast to Rituximab, mAb 1.5.3 is a fully human antibody and is thus anticipated to exhibit a longer serum half-life with minimal immunogenicity following repeated administration. In sum, these results demonstrate the superior anti-tumor activity of mAb 1.5.3 relative to Rituximab and its potential for improved clinical activity in the treatment of B-cell malignancies.

Depletion of Normal and Malignant B cells with a CD37-specific SMIP molecule

2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 3063-3063
Author(s):  
C. Cerveny ◽  
L. Grosmaire ◽  
E. Espling ◽  
R. Bader ◽  
C. Nilsson ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Target Cell ◽  
Growth Arrest ◽  
Xenograft Model ◽  
B Cell Malignancies ◽  
B Lymphoma ◽  
Anti Tumor Activity

3063 Background: CD37 is a member of the tetraspanin family expressed at high levels by normal mature B cells and by most B cell malignancies. Previously, an antibody to CD37 has been labeled with 131I and tested in clinical trials for therapy of NHL. Treatment with 131I-MB-1, resulted in durable tumor remissions in patients lasting from 4 to 11 months (Press OW, Eary JF, Badger CC, et al. Treatment of refractory non-Hodgkin’s lymphoma with radiolabeled MB-1 (anti-CD37) antibody. J Clin Oncol. 1989;7:1027–1038). Here we assess the functional properties and therapeutic potential of a small modular immunopharmaceutical (SMIP) targeting CD37. Methods: Growth arrest and apoptosis of B lymphoma cell lines was assessed. ADCC activity was evaluated using BJAB targets and human peripheral blood mononuclear cells (PBMC) effectors. Drug-drug interactions were assessed by the Combination Index method. In vivo studies were performed utilizing established human B cell tumor xenografts in nude mice. Results: A CD37-directed SMIP drug candidate mediated growth arrest, apoptosis and ADCC, but not CDC, towards B lymphoma cell lines. The protein showed significant anti-tumor activity in a mouse xenograft model, and selectively depleted normal human B cells in short term cultures of PBMC. When combined with rituximab, the molecule increased apoptosis, C1q binding, and C’ dependent target cell death in vitro, and increased anti-tumor activity in vivo in a xenograft model. Conclusions: In vitro and in vivo characterization of the CD37-targeted SMIP drug suggest a potent capacity to eliminate target cells through combined effects of direct target cell signaling and effector cell recruitment. CD37-mediated growth was synergistic with standard chemotherapies in vitro and showed additive in vivo activity with CD20-targeted therapy. On the basis of these data CD37-directed SMIP therapy is being developed for clinical evaluation against B cell malignancies. No significant financial relationships to disclose.

Blockade of the CD47/SIRPα Checkpoint Potentiates the Anti-Tumor Efficacy of Tafasitamab

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 11-12
Author(s):  
Doris Mangelberger ◽  
Christian Augsberger ◽  
Karin Landgraf ◽  
Christina Heitmüller ◽  
Stefan Steidl
Keyword(s):  
Monoclonal Antibody ◽  
Tumor Growth ◽  
B Cell ◽  
Tumor Model ◽  
B Cell Lymphoma ◽  
Checkpoint Blockade ◽  
Subcutaneous Tumor ◽  
Anti Tumor Activity

Introduction Tafasitamab (MOR208) is an Fc-enhanced, humanized, monoclonal antibody that targets CD19 and has shown promising clinical activity in patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL). CD19 is homogeneously expressed among different B-cell malignancies, and the binding of tafasitamab to CD19 directly mediates cell death, induces antibody-dependent cellular cytotoxicity and antibody-dependent cellular phagocytosis. Aiming to potentiate the tafasitamab-mediated "eat me" signal, we tested a combination with a CD47-directed monoclonal antibody (mAb) to inhibit the CD47/SIRPα "don't eat me" signal and further enhance macrophage-mediated phagocytosis. Preclinical studies demonstrated that blocking the CD47/SIRPα checkpoint in combination with antibodies, such as rituximab, increased phagocytosis by macrophages, resulting in effective anti-tumor effects in non-Hodgkin lymphoma (NHL) (Chao, et al. 2010). Additionally, the combination of the anti-CD47, magrolimab, and the anti-CD20, rituximab, demonstrated beneficial outcomes for patients with refractory NHL (Advani, et al. 2019). Here, we present in vitro and in vivo data on the combinatory effect of tafasitamab and an anti-CD47 mAb in preclinical models of Burkitt's lymphoma (BL). Methods During in vitro studies, CD14+ monocytes were isolated from the whole blood of healthy volunteers and differentiated with 50 ng/mL M-CSF for 6 days. ADCP was analyzed by flow cytometry in co-culture experiments with Ramos cells (BL) after 3 hours of treatment with tafasitamab and anti-CD47 mAb (clone B6H12). In vivo, the combination of tafasitamab with an anti-CD47 mAb was tested in a Ramos disseminated survival and subcutaneous tumor model in SCID and NOD-SCID mice, respectively. In both models, tafasitamab was administered therapeutically twice a week either at 3 mg/kg (disseminated) or 10 mg/kg (subcutaneous) for max. 4 weeks. The anti-CD47 mAb was administered at 4 mg/kg three times per week. Main study readouts were to assess animal survival and any delays in tumor growth. Results The combination of tafasitamab + CD47/SIRPα checkpoint blockade enhanced ADCP activity of primary M2 macrophages on BL-derived Ramos cells, in comparison with the anti-CD47 mAb or tafasitamab monotherapies (Figure 1A). In vivo, a significant increase in anti-tumor activity was observed with the combination of tafasitamab + anti-CD47 mAb. In the Ramos disseminated survival model, the combination showed an increased life span (ILS) of &gt;182% compared with tafasitamab monotherapy control, with an overall survival of all animals treated with the combination (15/15) until the end of the study (Day 99 post-cell injection). Additionally, pronounced anti-tumor efficacies were detected in the Ramos subcutaneous tumor model. Here, the combination resulted in a significant delay in tumor growth compared with the tafasitamab or anti-CD47 mAb monotherapies (ILS &gt;175% tafasitamab and ILS &gt;72% anti-CD47 mAb vs tafasitamab + B6H12) (Figure 1B). Conclusions The ADCP activity of primary macrophages was increased by combining tafasitamab with an anti-CD47 mAb in vitro, resulting in enhanced anti-tumor activity compared with tafasitamab or anti-CD47 mAb monotherapies in vivo. Overall, results indicate the combination of tafasitamab with a CD47/SIRPα checkpoint blockade may be a promising novel combination approach for lymphoma therapy. Disclosures Mangelberger: MorphoSys AG: Current Employment. Augsberger:MorphoSys AG: Current Employment. Landgraf:MorphoSys AG: Current Employment. Heitmüller:MorphoSys AG: Current Employment. Steidl:MorphoSys AG: Current Employment.

Obatoclax and Bortezomib Therapy Results in Disruption of the p53-Mediated Apoptosis/Autophagy Pathway and Is Associated with Potent Synergistic Anti-Tumor Activity against Rituximab-Chemotherapy-Sensitive and -Resistant B-Cell Lymphoma.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 288-288 ◽  
Author(s):  
Francisco Hernandez-Ilizaliturri ◽  
Ping-Chiao Tsio ◽  
Ryan Campagna ◽  
Cory Marvis ◽  
Wasif Riaz ◽  
...  
Keyword(s):  
Cell Death ◽  
B Cell ◽  
Tumor Cells ◽  
Primary Tumor ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Synergistic Activity ◽  
Knock Down ◽  
Anti Tumor Activity

Abstract Abstract 288 Interaction between the members of the BH3 domain family of proteins plays an important role in the development, progression, and prognosis of various subtypes of B-cell lymphoma. Therapies that selectively induce a pro-apoptotic environment are an attractive strategy to overcome chemotherapy-resistance in B-cell lymphoma. The proteasome is an important regulator of various members of Bcl-2 family proteins. We previously demonstrated that obatoclax, a novel BH3 mimetic, was able to enhance the anti-tumor activity of rituximab and chemotherapy agents and induced both apoptosis and autophagy in B-cell lymphoma. In an attempt to increase the therapeutic options for B-cell lymphoma patients we studied the biological effects of obatoclax in combination with bortezomib in a panel of rituximab-[chemotherapy]-sensitive (RSCL) and rituximab-[chemotherapy]-resistant cell lines (RRCL), as well as primary tumor cells isolated from 45 NHL patient biopsy samples with various subtypes of B-cell lymphoma: (ie including, DLBCL, follicular lymphoma (FL), marginal zone lymphoma (MZL), mantle cell lymphoma (MCL), and Hodgkin lymphoma (HL)]. Patient-derived primary tumor cells were isolated from fresh biopsies by negative selection using magnetic beads. Transient knock-down of p53 and Noxa were performed to determine the role of p53 in the anti-tumor activity of bortezomib or obatoclax, respectively. NHL cells were exposed in vitro to escalating doses of obataclox (0, 2, 5, 10 and 20mM) and/or bortezomib (0, 2, 10 and 20nM) for 24 and 48 hrs. Cell death was determined by the cell glow luminescent assay and DNA synthesis was evaluated by standard [3H]-Thymidine incorporation assays at 24 and 48 hrs. Changes in mitochondrial potential and cell proliferation were determined by alamar blue reduction using a kinetic assay measuring activity at 4 hr intervals for 24 and 48 hrs. In vitro exposure of RRCL, RSCL, and primary tumor cells to the combination of obatoclax plus bortezomib demonstrated significant synergistic activity compared to controls. Patients with DLBCL (n=15) and FL (N=12) demonstrated significant sensitivity to this combination. Of note, activity was observed in patients with either de novo or relapsed/refractory germinal B-cell (GBC) or activated B-cell (ABC) DLBCL (as characterized by the Han's criteria). Additionally, cell death induced by obatoclax or bortezomib could be inhibited by transient knock-down of p53 or Noxa, respectively. In summary, deregulation of apoptosis by BH3 inhibition with obatoclax and bortezomib results in cell death and antiproliferation not only in RSCL and RRCL, but also in primary tumor cells derived from “treatment-naïve or refractory” DLBCL and FL patients. Data strongly suggests that both p53 and Noxa have pivotal roles in response to obatoclax and bortezomib. The combination of obatoclax plus bortezomib has the potential of becoming a novel and potent therapeutic strategy in the treatment of B-cell lymphoma in the future. Research, in part, supported as part of a subproject on NIH PO1 grant CA103985-1 awarded to the Garden State Cancer Center, Belleville, NJ and NHI R-01 grant R01 CA136907-01A1 awarded to Roswell Park Cancer Institute Disclosures: No relevant conflicts of interest to declare.

CD32B, the human inhibitory Fc-γ receptor IIB, as a target for monoclonal antibody therapy of B-cell lymphoma

Blood ◽  
2006 ◽  
Vol 108 (7) ◽  
pp. 2384-2391 ◽  
Author(s):  
Christopher T. Rankin ◽  
Maria-Concetta Veri ◽  
Sergey Gorlatov ◽  
Nadine Tuaillon ◽  
Steve Burke ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
B Cell ◽  
Mononuclear Cells ◽  
Cell Lymphoma ◽  
Xenograft Model ◽  
B Cell Lymphoma ◽  
Tumor Growth Rate ◽  
B Cell Malignancies ◽  
Mouse Xenograft Model

Abstract Human CD32B (FcγRIIB), the low-affinity inhibitory receptor for IgG, is the predominant Fc receptor (FcR) present on B cells. Immunohistochemical and expression studies have identified CD32B expression in a variety of B-cell malignancies, suggesting that CD32B is a potential immunotherapeutic target for B-cell malignancies. A high-affinity monoclonal antibody (mAb 2B6), from a novel panel of anti–human CD32B–specific mAbs, was chimerized (ch2B6) and humanized (hu2B6-3.5). Both ch2B6 and hu2B6-3.5 were capable of directing cytotoxicity by peripheral blood mononuclear cells and monocyte-derived macrophages against B-lymphoma lines in vitro. In a human B-cell lymphoma mouse xenograft model, administration of ch2B6 or hu2B6-3.5 reduced tumor growth rate and improved tumor-free survival. Both the in vitro and in vivo activities of 2B6 required an intact Fc, suggesting an FcR-mediated mechanism of action. These data support the hypothesis that CD32B is a viable target for mAb treatment of B-cell lymphoproliferative disorders.

Pre-Clinical Development of Adct-402, a Novel Pyrrolobenzodiazepine (PBD)-Based Antibody Drug Conjugate (ADC) Targeting CD19-Expressing B-Cell Malignancies

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 1564-1564 ◽  
Author(s):  
Francesca Zammarchi ◽  
David G. Williams ◽  
Lauren Adams ◽  
Karin Havenith ◽  
Simon Chivers ◽  
...  
Keyword(s):  
Single Dose ◽  
B Cell ◽  
Cell Lines ◽  
Xenograft Model ◽  
B Cell Malignancies ◽  
Employment Equity ◽  
Equity Ownership ◽  
Anti Tumor Activity

Abstract Human CD19 antigen is a 95 kilodalton type I transmembrane glycoprotein belonging to the immunoglobulin superfamily (Wang, Wei, & Liu, 2012). The role of CD19, both in health and disease, is well studied, and the therapeutic efficacy and safety of CD19 modulation have been well defined over several decades (Scheuermann & Racila, 1995). In normal human tissue, expression of CD19 is limited to the various stages of B-cell development and differentiation (except plasma cells) and its expression is maintained on the majority of B-cell malignancies, including B-cell leukemia and non-Hodgkin lymphomas of B-cell origin. CD19 has rapid internalization kinetics and it is not shed into the circulation (Blanc et al., 2011; Gerber et al., 2009). All these features make CD19 an attractive target for the development of an ADC to treat B-cell malignancies. ADCT-402 is an ADC composed of a humanized antibody directed against human CD19, stochastically conjugated via a valine-alanine cleavable, maleimide linker to a PBD dimer cytotoxin. PBD dimers are highly efficient anticancer drugs that covalently bind in the minor groove of DNA and form cytotoxic DNA interstrand cross-links. The average drug to antibody ratio of ADCT-402 is 2.3 ± 0.3, as shown by hydrophobic interaction chromatography and reverse-phase HPLC. In vitro, ADCT-402 demonstrated potent cytotoxicity in a panel of human-derived cell lines of differing levels of CD19, while its potency was strongly reduced in CD19-negative cell lines. In vivo, ADCT-402 demonstrated dose-dependent anti-tumor activity in a subcutaneously implanted human Burkitt's lymphoma-derived Ramos xenograft model, where a single dose at 0.33 mg/kg induced significantly delayed tumor growth compared to the vehicle-treated mice and at 0.66 mg/kg and 1 mg/kg gave 4/10 and 10/10 tumor-free survivors, respectively. In the same model, ADCT-402 showed remarkably superior anti-tumor activity compared to both maytansinoid- and auristatin-based CD19-targeting ADCs, when they were tested at the same dose and schedule (1 mg/kg, single dose). Moreover, ADCT-402 mediated an impressive increase in survival compared to both vehicle-treated and isotype control ADC-treated mice in the disseminated Ramos xenograft model when tested as a single dose at 0.33 mg/kg or 1 mg/kg. For example, a single dose of ADCT-402 at 1 mg/kg resulted in 10/10 survivors at day 91, while there were 0/10 survivors at day 19 in the group of animals treated with either the vehicle control or with a single dose of the non-binding, control ADC at 1 mg/kg. In rat, a single dose of ADCT-402 at 2 mg/kg was well tolerated with no adverse signs or hematologic effects. Altogether, these data show the potent and specific anti-tumor activity of ADCT-402 against CD19-expressing B-cell malignancies, both in vitro and in vivo, and warrant further development of this ADC into the clinic. Disclosures Zammarchi: ADC Therapeutics: Employment. Williams:Spirogen/Medimmune: Employment. Adams:Spirogen/Medimmune: Employment, Equity Ownership. Havenith:ADC Therapeutics: Employment. Chivers:ADC Therapeutics: Employment. D'Hooge:Spirogen/Medimmune: Employment, Equity Ownership. Howard:ADCT Spirogen/Medimmune: Employment, Equity Ownership, Patents & Royalties. Hartley:ADCT Spirogen/Medimmune: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees. van Berkel:ADC Therapeutics: Employment, Equity Ownership, Patents & Royalties.

scholarly journals Targeted inhibition of PI3Kα/δ is synergistic with BCL-2 blockade in genetically defined subtypes of DLBCL

Blood ◽  
2019 ◽  
Vol 133 (1) ◽  
pp. 70-80 ◽  
Author(s):  
Kamil Bojarczuk ◽  
Kirsty Wienand ◽  
Jeremy A. Ryan ◽  
Linfeng Chen ◽  
Mariana Villalobos-Ortiz ◽  
...  
Keyword(s):  
B Cell ◽  
Cell Lymphoma ◽  
Single Agent ◽  
Xenograft Model ◽  
Myeloid Cell ◽  
B Cell Lymphoma ◽  
Cell Receptor ◽  
Synergistic Activity ◽  
Genetic Bases

Abstract Inhibition of the B-cell receptor (BCR) signaling pathway is a promising treatment strategy in multiple B-cell malignancies. However, the role of BCR blockade in diffuse large B-cell lymphoma (DLBCL) remains undefined. We recently characterized primary DLBCL subsets with distinct genetic bases for perturbed BCR/phosphoinositide 3-kinase (PI3K) signaling and dysregulated B-cell lymphoma 2 (BCL-2) expression. Herein, we explore the activity of PI3K inhibitors and BCL-2 blockade in a panel of functionally and genetically characterized DLBCL cell line models. A PI3K inhibitor with predominant α/δ activity, copanlisib, exhibited the highest cytotoxicity in all BCR-dependent DLBCLs. The proapoptotic effect of copanlisib was associated with DLBCL subtype-specific dysregulated expression of BCL-2 family members including harakiri (HRK) and its antiapoptotic partner BCL extra large (BCL-xL), BCL2 related protein A1, myeloid cell leukemia 1 (MCL-1), and BCL2 interacting mediator of cell death. Using functional BH3 profiling, we found that the cytotoxic activity of copanlisib was primarily mediated through BCL-xL and MCL-1–dependent mechanisms that might complement BCL-2 blockade. For these reasons, we evaluated single-agent activity of venetoclax in the DLBCLs and identified a subset with limited sensitivity to BCL-2 blockade despite having genetic bases of BCL-2 dysregulation. As these were largely BCR-dependent DLBCLs, we hypothesized that combined inhibition of PI3Kα/δ and BCL-2 would perturb BCR-dependent and BCL-2–mediated survival pathways. Indeed, we observed synergistic activity of copanlisib/venetoclax in BCR-dependent DLBCLs with genetic bases for BCL-2 dysregulation in vitro and confirmed these findings in a xenograft model. These results provide preclinical evidence for the rational combination of PI3Kα/δ and BCL-2 blockade in genetically defined DLBCLs.

The Monoclonal Antibody nBT062 Conjugated to Cytotoxic Maytansinoids Has Potent and Selective Cytotoxicity against CD138 Positive Multiple Myeloma Cells in Vitro and in Vivo.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1716-1716 ◽  
Author(s):  
Hiroshi Ikeda ◽  
Teru Hideshima ◽  
Robert J. Lutz ◽  
Sonia Vallet ◽  
Samantha Pozzi ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Monoclonal Antibody ◽  
Tumor Cells ◽  
Cell Lines ◽  
Xenograft Model ◽  
Growth Delay ◽  
Selective Cytotoxicity ◽  
Bystander Killing

Abstract CD138 is expressed on differentiated plasma cells and is involved in the development and/or proliferation of multiple myeloma (MM), for which it is a primary diagnostic marker. In this study, we report that immunoconjugates comprised of the murine/human chimeric CD138-specific monoclonal antibody nBT062 conjugated with highly cytotoxic maytansinoid derivatives (nBT062-SMCC-DM1, nBT062-SPDB-DM4 and nBT062-SPP-DM1) showed cytotoxic activity against CD138-positive MM cells both in vitro and in vivo. These agents demonstrated cytotoxicity against OPM1 and RPMI8226 (CD138-positive MM cell lines) in a dose and time-dependent fashion and were also cytotoxic against primary tumor cells from MM patients. Minimal cytotoxicity was noted in CD138-negative cell lines and no activity was observed against peripheral blood mononuclear cells from healthy volunteers, suggesting that CD138-targeting is important for immunoconjugate-mediated cytotoxicity. Examination of the mechanism of action whereby these immunoconjugates induced cytotoxicity in MM cells demonstrated that treatment triggered G2/M cell cycle arrest, followed by apoptosis associated with cleavage of PARP and caspase-3, -8 and -9. Neither interleukin-6 nor insulin-like growth factor-I could overcome the apoptotic effect of these agents. The level of soluble (s)CD138 in the BM plasma from 15 MM patients was evaluated to determine the potential impact of sCD138 on immunoconjugate function. The sCD138 level in BM plasma was found to be significantly lower than that present in MM cell culture supernatants where potent in vitro cytotoxicity was observed, suggesting that sCD138 levels in MM patient BM plasma would not interfere with immunoconjugate activity. Because adhesion to bone marrow stromal cells (BMSCs) triggers cell adhesion mediated drug resistance to conventional therapies, we next examined the effects of the conjugates on MM cell growth in the context of BMSC. Co-culture of MM cells with BMSCs, which protects against dexamethasoneinduced death, had no impact on the cytotoxicity of the immunoconjugates. The in vivo efficacy of these immunoconjugates was also evaluated in SCID mice bearing established CD138-positive MM xenografts and in a SCID-human bone xenograft model of myeloma. Significant tumor growth delay or regressions were observed at immunoconjugate concentrations that were well tolerated in all models tested. The ability of these agents to mediate bystander killing of proximal CD138-negative cells was also evaluated. While nBT062-SPDB-DM4 was inactive against CD138-negative Namalwa cells cultured alone, significant killing of these CD138-negative cells by nBT062-SPDB-DM4 was observed when mixed with CD138-positive OPM2 cells. This bystander killing may contribute to the eradication of MM tumors by disrupting the tumor microenvironment and/or killing CD138-negative MM tumor cells, such as the putative CD138 negative myeloma stem cells. These studies demonstrate strong evidence of in vitro and in vivo selective cytotoxicity of these immunoconjugates and provide the preclinical framework supporting evaluation of nBT062-based immunoconjugates in clinical trials to improve patient outcome in MM.

The DAC Inhibitor LBH589 Is Highly Effective in Both “Therapy”-Sensitive and -Resistant Lymphomas and Enhances the Anti-Tumor Activity of Chemotherapy Agents, Monoclonal Antibodies, and Bortezomib

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 4984-4984
Author(s):  
Ilir Maraj ◽  
Francisco J. Hernandez-Ilizaliturri ◽  
Mohammad M Chisti ◽  
Myron S. Czuczman
Keyword(s):  
Monoclonal Antibodies ◽  
B Cell ◽  
Tumor Cells ◽  
Class I ◽  
Synergistic Activity ◽  
B Cell Lymphomas ◽  
Lymphoma Cells ◽  
Target Proteins ◽  
Chemotherapy Agents ◽  
Anti Tumor Activity

Abstract Deacetylases (DACs) are enzymes that remove the acetyl groups from target proteins, leading to regulation of gene transcription and other cellular processes. Histones are one of the target proteins, which is why DACs (Class I) are sometimes referred to as histone deacetylases (HDACs). DACs also target non-histone proteins, which include transcription factors, a-tubulin, and HSP90 (Class II DACs). LBH589 is a novel and potent DAC Inhibitor that inhibits both class I and II of DAC activity, inducing cell death in tumor cells undergoing pre-clinical and clinical testing. Other investigators had demonstrated that DACs can down-regulate Bcl-2 expression in lymphoma cells (Duan, Heckman, Mol Cell Biol.2005; 25(5):1608-19), and potentially overcome chemotherapy resistance in B-cell lymphomas. In our efforts to develop more therapeutic options for refractory/resistant B-cell lymphomas we studied the effects of LBH589 at various doses (2nM to 20nM) and schedules of administration (before, after or concurrent administration) in the anti-tumor activity of chemotherapy agents and monoclonal antibodies in a panel of rituximab-sensitive (RSCL) (Raji and RL cells) and rituximab-resistant cell lines (Raji 2R, Raji 4RH and RL-4RH) (RRCL). In addition, we utilized lymphoma cells isolated from patients with treatment-naïve or refractory/relapsed B-cell lymphomas. Patient-derived tumor cells were isolated from fresh specimens by negative selection using magnetic beads. NHL cells lines were exposed to the following chemotherapy agents or monoclonal antibodies: CDDP (1 to 100mM), Doxorubicin (4 to 16mM), Vincristine (1 to 5mM), Bortezomib (1 to 10nM) or Rituximab (10mg/ml), A20 (10mg/ml), or Trastuzumab (Isotype, 10mg) alone or in combination with LBH589. In dose-sequence studies the treatment with LBH589 preceded or followed in vitro exposure to the chemotherapy agent or the monoclonal antibody by 24 hrs. Changes in mitochondrial potential and cell proliferation were determined by alamar blue reduction using a kinetic assay measuring activity at 15 minute intervals for 24 and 48 hrs. Patient-derived tumor cells (10 samples up to date) were exposed to either LBH589, bortezomib or both at different doses. Changes in ATP content were determined using the cell titer glow assay. LBH859 was active as a single agent against rituximab-sensitive or resistant cells tested as well as in tumor cells derived from lymphoma patients. Significant anti-tumor activity was more pronounced after 48 hrs of drug exposure even at 2nM doses of LBH859. In addition, significant synergistic activity was observed by combining LBH589 and chemotherapy agents (CDDP, doxorubicin or Vincristine), bortezomib or the two mAbs targeting CD20 studied (rituximab and veltuzumab). The sequence of administration impacted the responses observed with bortezomib and mAbs, but not the chemotherapy agents evaluated. Pre-incubation of NHL cells with LBH589 prior to bortezomib or mAb therapy leads to the maximum optimization of each agent than another sequence of administration. In summary, our data suggests that LBH589 is active against various RSCL, RRCL and patient-derived tumor cells and potentiate the anti-tumor effects of chemotherapy agents, mAbs targeting CD20, and bortezomib. Findings suggest that LBH589 added to systemic anti-CD20 and/or chemotherapy could result in a novel and potent treatment strategy against B-cell lymphomas.

TRU-016, An Anti-CD37 SMIP™ Biologic, In Combination with Other Therapeutic Drugs In Models of Non-Hodgkin's Lymphoma

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3931-3931 ◽  
Author(s):  
Paul A. Algate ◽  
Jennifer Wiens ◽  
Christy Nilsson ◽  
Mien Sho ◽  
Debra T. Chao ◽  
...  
Keyword(s):  
Tumor Growth ◽  
Follicular Lymphoma ◽  
B Cell ◽  
Cell Lymphoma ◽  
Combination Index ◽  
Growth Delay ◽  
Tumor Growth Delay ◽  
B Cell Malignancies

Abstract Abstract 3931 Background: CD37 is a 50–55 kDa heavily glycosylated member of the tetraspanin superfamily of molecules. This cell surface protein is expressed on normal and transformed B-cells, and has been implicated in diverse processes including cellular activation and proliferation, cell motility, and cell-cell adhesion. TRU-016 is a novel humanized anti-CD37 SMIP™ protein. Pre-clinical studies have demonstrated that anti-CD37 SMIP™ protein mediates caspase-independent direct killing of normal and malignant B-cells, a mechanism of action that appears to be different than CD20 therapies. In addition, TRU-016 results in indirect killing through NK cell mediated SMIP-protein directed cellular cytotoxicity (SDCC). The therapeutic potential of TRU-016 against several subsets of B-cell malignancies is currently being investigated in the clinic. Methods: The ability of TRU-016 to interact and increase cell killing with established therapeutics rituximab (anti-CD20 antibody), bendamustine (bi-functional alkylating agent/nucleoside analog), LY294002 (PI3K inhibitor) and temsirolimus (mTOR inhibitor) was investigated in vitro using the Rec-1 (mantle cell lymphoma) and SU-DHL-6 (diffuse large B cell lymphoma) cell lines. Individual drugs were tested in combination with TRU-016 as well as in a multiple drug cocktail. Combination index analyses were performed for drug combinations over the 20–90% effect levels. To determine whether in vitro synergy could be recapitulated in vivo, DoHH-2 (follicular lymphoma) xenografts were treated with TRU-016, bendamustine, and the combination of TRU-016 and bendamustine with or without rituximab. Furthermore, the effect of the dosing schedule with the combination of TRU-016 and rituximab was explored by comparing the treatment over a short time period to an extended (maintenance) dosing regimen. CD37 expression on the tumor xenografts was evaluated post different treatment by immunohistochemistry. Results: Combination index analyses determined that the killing effects of TRU-016 was synergistic with rituximab, bendamustine and temsirolimus in NHL models. Furthermore, TRU-016 provided additional efficacy when added to the combination of rituximab and bendamustine. In vivo results demonstrated that the in vitro synergy results were applicable to a more complex in vivo disease model. The combination of TRU-016 with bendamustine or rituximab resulted in increased tumor growth delay compared to that attained with the individual drugs. The addition of TRU-016 to the combination of bendamustine and rituximab resulted in increased tumor growth delay compared to the two drugs alone. The observed efficacy of the combination of TRU-016 and rituximab could be extended with repeated (maintenance) dosing with tumor free survival being observed beyond the 35 days of dosing. The combination of TRU-016 with temsirolimus also resulted in a reduction of tumor growth compared to either molecule alone. CD37 target expression was detected in the xenograft tumors post-treatment with all drugs tested. Conclusions: TRU-016 in combination with rituximab, bendamustine or temsirolimus increased cell killing of NHL cells in vitro over that observed for each agent alone. Furthermore, the triple combination of TRU-016 with rituximab, bendamustine or temsirolimus displayed greater anti-tumor activity in vivo than each of the agents alone against a follicular lymphoma tumor model. The addition of TRU-016 to a combination of rituximab and bendamustine resulted in increased killing in vitro and in vivo. The combinatorial activity of TRU-016 and rituximab in vivo was increased when the drugs were administered over a longer period. These results provide preclinical rationale for the potential different combinations of TRU-016 with several established therapeutics for the treatment of NHL and related B-cell malignancies. Disclosures: Algate: Trubion Pharmaceuticals: Employment. Wiens:Trubion Pharmaceuticals: Employment. Nilsson:Trubion Pharmaceuticals: Employment. Sho:Facet/Abbott: Employment. Chao:Facet/Abbott: Employment. Starling:Facet/Abbott: Employment. Gordon:Trubion Pharmaceuticals: Employment.

Sign in / Sign up

Export Citation Format

Share Document