AO-176, a Differentiated Clinical-Stage Anti-CD47 Antibody, Demonstrates Potent Anti-Tumor Activity across Multiple Preclinical Models of B Cell Neoplasms

Abstract Upregulation of CD47, the "don't eat me" signal, on the surface of tumors to evade immune surveillance is a common escape mechanism utilized during hematological malignancy and solid tumor development, progression, and relapse. We recently reported that AO-176, a clinical stage humanized anti-CD47 IgG2 antibody, possesses differentiated characteristics such as preferential binding of tumor cells compared to normal cells, negligible binding to red blood cells, non-ADCC direct tumor killing and elicits immunogenic cell death and DAMP induction, all in addition to single-agent phagocytosis. In vivo, AO-176 has exhibited broad anti-tumor activity in preclinical xenograft models of multiple myeloma (MM), acute myeloid leukemia, T cell acute lymphoblastic leukemia, and Burkitt lymphoma. In this study, the anti-tumor activity of AO-176 in an expanded set of preclinical models of B cell neoplasms was evaluated. We assessed In vivo anti-tumor activity in a diffuse large B cell lymphoma (DLBCL) preclinical xenograft model by inoculating Toledo cells into NSG mice and treating once weekly with either 25 mg/kg AO-176 or human IgG2 isotype control. Treatment with AO-176 resulted in profound tumor shrinkage, achieved complete responses in 8/10 mice, and extended survival for all treated mice through the 46 day dosing period, compared to all isotype control treated tumors reaching endpoint by day 21. Having previously observed significant tumor shrinkage and extension of survival in subcutaneous xenograft models of MM, we sought to evaluate anti-tumor activity of AO-176 in an orthotopic model of MM. Luciferase expressing RPMI-8226 cells were inoculated via intratibial injection into NOD-SCID mice and treated with either 25 mg/kg of AO-176 or human IgG2 isotype control once weekly. AO-176-treated mice showed significant reductions of bioluminescence on study days 7, 21, 35, and 41, and serum paraprotein at study end. Evaluation of bone lesions by x-ray showed significantly reduced average bone lysis score in the AO-176 treatment group at study day 41. We then compared the anti-tumor activity of AO-176 against the second generation proteosome inhibitor carfilzomib in a myeloma xenograft model. AO-176 dosed at 25 mg/kg once weekly achieved 72% TGI, compared to 47% and 27% TGI for tumors treated with 5 mg/kg and 2.5 mg/kg carfilzomib at day 29 post treatment. To elucidate the pathways and processes that may be underpinning the anti-tumor activity of AO-176, we performed bulk RNA sequencing on AO-176 or isotype control-treated tumors harvested at multiple time points from a MM xenograft model we previously reported as exhibiting profound sensitivity to AO-176 in vivo. Murine transcripts from harvested tumor RNA were evaluated to assess differences in immune infiltrate resulting from AO-176 treatment. Days 3 and 7 post treatment with AO-176 showed the greatest number of differentially expressed genes compared to control treated tumors. The top enriched pathway on day 3 was microglia phagocytosis. Principal component analysis of gene expression indicated partitioning of day 3 post AO-176 treatment from the rest of the groups. Furthermore, deconvolution of abundances of infiltrating immune cells using CIBERSORT via TIMER analytical tool showed an enrichment of macrophages relative to other cell types on day 3 post treatment. To extend our RNA sequencing findings, we then sought to evaluate intratumoral immune cell populations after AO-176 treatment in a subcutaneous MM xenograft model. MM cells were inoculated into NOD-SCID mice, then treated with 25 mg/kg AO-176 or human IgG2 isotype control. At 48 hours post treatment, tumors were harvested, and we observed an increase of macrophages in the AO-176 treated tumors, confirming our previous results. In summary, the robust preclinical data in DLBCL and MM warrants further development of AO-176 for treatment of hematological malignancies. AO-176 is being evaluated in phase 1/2 clinical trials for the treatment of patients with solid tumors (NCT03834948) and with MM (NCT04445701). Disclosures Wilson: Arch Oncology: Current Employment. Richards: Arch Oncology: Current Employment. Andrejeva: Arch Oncology: Current Employment. Capoccia: Arch Oncology: Current Employment. Puro: Arch Oncology: Current Employment. Donio: Arch Oncology: Current Employment. Hiebsch: Arch Oncology: Current Employment. Kashyap: Arch Oncology: Current Employment. Pereira: Arch Oncology: Current Employment.

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

Journal of Clinical Oncology ◽

10.1200/jco.2007.25.18_suppl.3063 ◽

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.

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Klotho/IGF-1R Regulates Tumor Growth and Predicts Prognosis in Diffuse Large B-Cell Lymphoma

Blood ◽

10.1182/blood.v128.22.2924.2924 ◽

2016 ◽

Vol 128 (22) ◽

pp. 2924-2924

Author(s):

Xiangxiang Zhou ◽

Ying Li ◽

Xinyu Li ◽

Lingyun Geng ◽

Ya Zhang ◽

...

Keyword(s):

Tumor Growth ◽

B Cell ◽

Cell Lines ◽

Xenograft Model ◽

B Cell Lymphoma ◽

Control Group ◽

Klotho Protein ◽

Xenograft Models

Abstract Introduction: Klotho is an anti-aging gene with an extracellular domain. Mice with Klotho knockout exhibited obvious impairment in B-cell development. Evolving evidence indicates that Klotho modulates the proliferation and survival via targeting insulin-like growth factor-1 receptor (IGF-1R) in several cancers. However, the expression and biological role of Klotho in B-cell non-Hodgkin lymphoma (B-NHL) has not been elucidated to date. We hypothesized that Klotho could modulate the tumor growth and predicts prognosis in diffuse large B-cell lymphoma (DLBCL) through inhibiting IGF-1R activation. The aim of this study is to characterize the functional significance of Klotho and the therapeutic potential of its secreted form in DLBCL. Methods: Lymph nodes samples from 50 de novo DLBCL and 20 reactive hyperplasia cases were collected with informed consents. Klotho expression were assessed by Immunohistochemistry. CD19+ B-cells and peripheral blood mononuclear cells were isolated with informed consents from healthy donors. Expression levels of Klotho mRNA and protein in DLBCL cells were determined by quantitative RT-PCR and western blotting. Lentivirus vectors either encoding Klotho (LV-KL) or empty lentiviral vector (LV-Con) were stably transfected into DLBCL cells. Cell viability and apoptosis were analyzed by cell counting kit-8 and Annexin V-PE/7AAD staining. Animal experiments were performed in accordance with the principles of the Institutional Animal Care. SCID-Beige mice were subcutaneously injected with DLBCL cells to establish xenograft model. Results: We observed markedly decreased level of Klotho protein in DLBCL lymph nodes (Fig. 1A). Expression of Klotho protein exhibited significantly negative correlation with Ann Arbor stage of DLBCL patients (p=0.002). Level of Klotho protein was negatively correlates with the media overall survival (OS), suggesting lower Klotho expression is associated with poor OS in DLBCL ((Fig. 1B, p=0.045). Reduction of Klotho was also confirmed in DLBCL cell lines at mRNA and protein level (Fig. 1C). We next functionally interrogated the role of Klotho in DLBCL cell lines and xenograft models. Stably expression of LV-KL in DLBCL cell lines resulted in dramatically decreased cell proliferation and incremental apoptotic rates when compared to LV-Con (Fig. 2A and B). We validated the changed expression of critical targets known to govern apoptosis in DLBCL cells transfected with LV-KL. Xenograft models with Klotho overexpression revealed significantly abrogated tumor growth compared to control group (Fig. 2C). Interestingly, lower levels of Ki67 were observed in mice treated with LV-KL (Fig. 2D). These results highlighted the proliferation-inhibitory and apoptosis-inductive activities of Klotho in DLBCL cells. The underlying mechanism driving the tumor suppressive potential of Klotho was investigated. Surprisingly, we observed that the Klotho-induced inhibition of cell viability was only fewer restored by IGF-1 in DLBCL cells transfected with LV-KL (Fig. 3A). Reductive phosphorylation of IGF-1R and its downstream targets (AKT and ERK1/2) were observed in DLBCL cells with Klotho overexpression (Fig. 3B). In addition, we evaluated the regulation of Klotho on IGF-1R signaling in vivo. Decreased phosphrolation of IGF-1R as well as its downstream targets were observed in mice treated with LV-KL compared to the control group (Fig. 3C). Lastly, we explored the activity of secreted Klotho protein (rhKL). The rhKL was found to be active in vitro and significantly reduced the viabilities of DLBCL cells (Fig. 3D). Moreover, combination with rhKL increased the sensitivity of DLBCL cells to adriamycin. The in vivo activity of rhKL in DLBCL xenograft model was also detected. Significantly decreased tumor volumes were noted in mice treated with rhKL compared with those treated with vehicle control (Fig. 3E). Moreover, reductive expression level of Ki67 was observed in rhKL-treated group (Fig. 3F). Conclusions: Our observations identified for the first time that loss of Klotho expression contributed to the development and poor prognosis via activating IGF-1R in DLBCL. Given the in vivo tumor suppressive activity of secreted Klotho protein, it may serve as a potential strategy for the development of novel therapeutic interventions for DLBCL. Figure 1 Figure 1. Figure 2 Figure 2. Figure 3 Figure 3. Disclosures No relevant conflicts of interest to declare.

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Efficacy of an Antagonistic Anti-CD40 Monoclonal Antibody, HCD122 (CHIR-12.12), in Preclinical Models of Human Non-Hodgkin’s Lymphoma and Hodgkin’s Disease.

Blood ◽

10.1182/blood.v108.11.230.230 ◽

2006 ◽

Vol 108 (11) ◽

pp. 230-230 ◽

Cited By ~ 6

Author(s):

Li Long ◽

Montesa Patawaran ◽

Xia Tong ◽

Seema Kantak ◽

Sharon L. Aukerman ◽

...

Keyword(s):

Antitumor Activity ◽

B Cell ◽

Cell Lines ◽

Xenograft Model ◽

Preclinical Models ◽

B Cell Malignancies ◽

Effector Cells ◽

Mantle Cell ◽

Xenograft Models ◽

Human B Cell

Abstract Non-Hodgkin’s lymphoma (NHL) and Hodgkin’s disease (HD) account for about 9% of new cancer cases annually or 64,000 cases per year in the United States. Although the survival rate has significantly improved recently due to new combination therapy regimens, an unmet medical need remains for refractory or resistant patients. HCD122 is a fully human antagonistic anti-CD40 therapeutic monoclonal antibody (mAb) with a dual mechanism of action: blocking CD40 and CD40 ligand (CD40L) interactions and mediating antibody-dependent cellular cytotoxicity (ADCC). CD40 is expressed in all human B-cell malignancies, and the CD40/CD40L interaction is important for tumor cell proliferation and survival. Previously HCD122 was shown to potently inhibit CD40L-induced human B-cell and follicular NHL cell proliferation, mediate ADCC against CD40-positive human malignant B-cell lines and inhibit tumor growth in Burkitt’s lymphoma and multiple myeloma xenograft models. In this study the antitumor activity of HCD122 was assessed in preclinical models of HD and other subtypes of human NHL, such as Mantle cell and Follicular lymphoma. CD40 was expressed in 5 of 7 established human HD and 11 of 12 NHL tumor cell lines tested, including Hs445, HDLM-2, KM-H2, L428, L1236, Jeko-1 and WSU-NHL. Using purified human NK cells as effector cells, HCD122 mediated potent ADCC against these cell lines in vitro with a picomolar EC50. When human macrophages were used as effector cells, HCD122 also induced antibody-dependent cellular phagocytosis (ADCP) against the NHL Daudi cell line and the HD cell line Hs445. The antitumor activity of HCD122 was further evaluated in vivo in EBV-negative NHL and HD xenograft models. When tested in a staged human Mantle cell lymphoma Jeko-1 s.c. xenograft model in which treatment was initiated when the mean tumor volume reached 100 mm3, HCD122 was highly efficacious and induced complete tumor regression in 70% (7/10) of treated animals when administered intraperitoneally at 1 mg/kg weekly for 4 weeks. In a staged human HD L428 s.c. xenograft model, which expresses CD20 as well as CD40, the antitumor activity of HCD122 was compared to rituximab. HCD122 was highly efficacious and induced a mean 74 % tumor growth inhibition (TGI) when administered at 0.1 mg/kg weekly for 3 weeks (p<0.001). At the same dose and schedule, rituximab achieved only 40% TGI (HCD122 vs. rituximab: p<0.001). These data combined with our previous studies in multiple myeloma and EBV-positive Burkitt’s lymphoma models show that HCD122 is a potent anti-CD40 antibody with pronounced antitumor activity in both EBV-positive and EBV-negative malignant B cell preclinical models. HCD122 is currently in Phase I clinical trials in B-cell malignancies.

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Efficacy of the Plk Inhibitor Volasertib in Preclinical Models of AML

Blood ◽

10.1182/blood.v124.21.2307.2307 ◽

2014 ◽

Vol 124 (21) ◽

pp. 2307-2307

Author(s):

Dorothea Rudolph ◽

Christoph Albrecht ◽

Lena Geiselmann ◽

Maria Antonietta Impagnatiello ◽

Pilar Garin-Chesa ◽

...

Keyword(s):

Bone Marrow ◽

Cell Lines ◽

Single Agent ◽

Preclinical Models ◽

Subcutaneous Xenograft ◽

Xenograft Models ◽

Proliferation Assays ◽

Anti Tumor Activity

Abstract Background: Polo-like kinase 1 (Plk1), a key regulator of cell cycle progression and accurate spindle assembly, is an attractive target for cancer drug discovery. We have previously shown that volasertib (BI 6727), a potent and selective small-molecule inhibitor of Plk, induces a distinct mitotic arrest phenotype in prometaphase (“polo-arrest”) with subsequent apoptosis in a variety of different cancer cell lines, irrespective of their mutational status. When used in vivo, volasertib administered intravenously shows potent anti-tumor activity in xenograft models of human epithelial cancers at well-tolerated doses. The present study was designed to extend the analysis of volasertib to additional preclinical models of human AML, including bone marrow samples from AML patients. Volasertib is the most advanced Plk inhibitor in clinical development and has demonstrated encouraging results in phase II clinical trials. It is currently being investigated in a phase III clinical trial in patients with previously untreated AML, who are ineligible for intensive remission induction therapy. Methods: A panel of human AML cell lines was used to evaluate pharmacodynamic biomarker modulation and anti-tumor effects of volasertib in vitro using FACS analysis, Western blot analysis and proliferation assays. This in vitro analysis of established AML cell lines was extended to proliferation assays using bone marrow samples from AML patients. In vivo anti-tumor activity of volasertib was tested in subcutaneous xenograft models as well as in multiple disseminated xenograft models of AML. Single-agent efficacy of volasertib and combination therapies were evaluated with existing and emerging AML drugs, including an approved cytotoxic drug (cytarabine), hypomethylating agents (decitabine, azacitidine) and a signal transduction inhibitor targeting FLT3 (quizartinib). Results: Volasertib potently inhibited proliferation of established AML cell lines in vitro with EC50 values of 16-169 nM. Proliferation assays with 15 ex vivo bone marrow samples from AML patients showed EC50 values of 8-8800 nM with a median EC50 of 37 nM. Volasertib showed potent anti-tumor activity at well tolerated doses in 3 subcutaneous xenograft models of AML (MV4-11, Molm-13 and a patient-derived AML model AML-6252). While single-agent volasertib at medium dose level (20 mg/kg q7d i.v. for 2 cycles) and single-agent cytarabine (100 mg/kg q3-4d i.p. for 2 cycles) showed moderate efficacy in the AML-6252 AML model, the combination showed improved efficacy. Moreover, efficacy of single-agent volasertib at high dose level (40 mg/kg q7d i.v. for 2 cycles) could be further improved by adding cytarabine to the treatment regime (Figure 1). A combination of volasertib with decitabine or azacitidine was tested in the MV4-11 subcutaneous AML xenograft model. Either combination therapy showed improved efficacy compared to the respective single-agent treatment groups. Volasertib showed also improved anti-tumor activity when tested in combination with the Flt-3 inhibitor quizartinib (5 or 10 mg/kg qd po for 2 cycles) in the MV4-11 AML model. While tumors in the quizartinib single agent treatment groups started to regrow around day 60 post treatment start, a combination with volasertib could control tumor growth long term until the study was terminated (day 87 post treatment start). Efficacy of volasertib was also tested in 3 disseminated xenograft models of AML (MV4-11, Molm-13 and THP-1). Efficacy read out in these disseminated models was based on tumor load measurements as detected by bioluminescence imaging and increased lifespan. Volasertib prolonged survival compared to vehicle treated animals in all three disseminated models of AML. Conclusions: These results indicate that volasertib is highly efficacious as a single agent in preclinical models of AML and shows potential for improved efficacy and good tolerability in combination with existing and emerging AML drugs. Figure 1: Efficacy of volasertib in combination with cytarabine in a patient-derived AML model (AML-6252) Figure 1:. Efficacy of volasertib in combination with cytarabine in a patient-derived AML model (AML-6252) Disclosures Rudolph: Boehringer Ingelheim RCV: Employment. Off Label Use: Volasertib is an investigational agent. Albrecht:Boehringer Ingelheim RCV GmbH & Co KG: Employment. Geiselmann:Boehringer Ingelheim RCV GmbH & Co KG: Employment. Impagnatiello:Boehringer Ingelheim RCV GmbH & Co KG: Employment. Garin-Chesa:Boehringer Ingelheim RCV: Employment. Wernitznig:Boehringer-Ingelheim: Employment. Moll:Boehringer-Ingelheim: Employment. Kraut:Boehringer Ingelheim RCV: Employment.

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In Vitro and In Vivo Targeting and Therapy of an Antibody-Drug Conjugate (IMMU-110) in B-Cell Malignancies.

Blood ◽

10.1182/blood.v104.11.3287.3287 ◽

2004 ◽

Vol 104 (11) ◽

pp. 3287-3287

Author(s):

Puja Sapra ◽

Rhona Stein ◽

Jennifer Pickett ◽

Serengulam V. Govindan ◽

Thomas M. Cardillo ◽

...

Keyword(s):

B Cell ◽

Cell Lines ◽

Specific Antibody ◽

Xenograft Model ◽

B Cell Lymphoma ◽

Scid Mice ◽

Significant Difference ◽

Xenograft Models

Abstract IMMU-110 is a drug immunoconjugate comprised of doxorubicin (DOX) conjugated to the humanized anti-CD74 monoclonal antibody (mAb), hLL1, at a DOX:mAb (mol/mol) ratio of 8:1. CD74 is a rapidly internalizing type-II transmembrane chaperone molecule associated with HLA-DR, and has high expression on human non-Hodgkin’s lymphoma (NHL) and multiple myeloma (MM) clinical specimens and cell lines. Here, we investigated the in vitro and in vivo efficacy of IMMU-110 in xenograft models of human NHL (Raji, Daudi) and MM (MC/CAR). In vitro cell binding of IMMU-110 with the CD74-positive cells was significantly higher than that of a non-specific isotype-matched mAb-DOX conjugate (DOX conjugated to a mAb against epithelial glycoprotein-1; DOX-hRS7), and was similar to that of naked hLL1. Both IMMU-110 and naked hLL1 bound CD74 with subnanomolar affinity. The in vitro cytotoxicity of IMMU-110 was significantly higher than non-specific antibody-DOX conjugate, DOX-hRS7, and was similar to free DOX in MC/CAR, Raji or Daudi human Burkitt’s lymphoma cells. In CD74-negative cell lines, IMMU-110 was significantly less toxic than free DOX, having similar cytotoxicity to DOX-hRS7. In vivo, IMMU-110 displayed a pharmacokinetic and biodistribution profile almost identical to that of hLL1 mAb. Both hLL1 mAb and IMMU-110 had a biphasic clearance from the circulation; the α and β half-life (t1/2) of IMMU-110 were 4.6 h and 157.9 h, respectively, and those of hLL1 were 5.4 h and 151.5 h, respectively. In biodistribution studies, no significant difference was observed between IMMU-110 and naked hLL1 with regards to normal tissue uptake. Neither IMMU-110 nor naked hLL1 mAb had a significant association with any normal body tissue. In therapy experiments, a single i.v. protein dose of 350 μg IMMU-110, injected 5 days after implantation of MC/CAR cells in SCID mice, resulted in curing 70% of the animals. Similar cure rates were observed when treatment with IMMU-110 was given 10 days after transplantation of MC/CAR cells. In the Raji xenograft model, 100% of animals were cured with a single protein dose of 120 μg IMMU-110, injected 5 days after implantation of cells. In survival studies, the efficacy of IMMU-110 was significantly better than naked hLL1, the combination of naked hLL1 and free DOX, or of a non-specific antibody-DOX conjugate, DOX-hRS7. In a tolerability study in SCID mice, no toxic effect of IMMU-110 was observed even at the highest dose tested (2.5 mg /mouse). In conclusion, treatment of B-cell lymphoma and myeloma xenograft models with single injections of IMMU-110 resulted in high levels of response and long-term survivors. IMMU-110 is being further developed as a potential therapeutic for the treatment of CD74-positive tumors.

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Eradication of Tumors in Pre-Clinical Models of Multiple Myeloma by Anti-CS1 Monoclonal Antibody HuLuc63: Mechanism of Action Studies.

Blood ◽

10.1182/blood.v108.11.3503.3503 ◽

2006 ◽

Vol 108 (11) ◽

pp. 3503-3503 ◽

Cited By ~ 5

Author(s):

Audie Rice ◽

Myles Dillon ◽

Anne van Abbema ◽

Lynne Jesaitis ◽

Melanie Wong ◽

...

Keyword(s):

Multiple Myeloma ◽

Mechanism Of Action ◽

Xenograft Model ◽

Fc Receptor ◽

Cell Surface Glycoprotein ◽

Xenograft Models ◽

Anti Tumor Activity ◽

Tumor Eradication

Abstract Introduction: We have recently shown that CS1 (CD2 subset 1, CRACC, SLAMF7), a cell surface glycoprotein of the CD2 family, is uniformly expressed on myeloma cells from multiple myeloma (MM) patients. Based on its high expression in MM and limited expression in normal cells, we propose CS1 as a novel and specific antibody target for the treatment of MM. Methods: A panel of monoclonal anti-CS1 antibodies (mAbs) was generated to identify a potential therapeutic candidate. MAb clones MuLuc63 and MuLuc90 were selected for testing in CS1 positive MM xenograft models in vivo in severe combined immunodeficient mice. HuLuc63, a humanized IgG1 version of MuLuc63, was generated as the potential therapeutic candidate for the treatment of MM. HuLuc63 and Fc-modified versions of HuLuc63 were tested for anti-tumor activity in mouse models vivo. In vitro antibody-dependent cellular cytotoxicity (ADCC) assays were performed to define the potential mechanism of action for HuLuc63. Results: Both MuLuc63 and MuLuc90 exhibited significant in vivo anti-tumor activity compared to isotype control antibodies in the L363 MM xenograft model. MuLuc63 was significantly more potent, resulting in rapid tumor eradication in most of the animals for the length of the study (~4 months). Based on these results, MuLuc63 was humanized to generate HuLuc63, which exhibited similar affinity for CS1 when compared to the mouse parent antibody. In two different MM xenograft models, L363 and OPM2, HuLuc63 exhibited significant anti-tumor activity resulting in tumor eradication in a high proportion of animals. To investigate the mechanism of action, two modified versions of HuLuc63 were tested in xenograft models. One version, HuLuc63-Ala,Ala, exhibits a mutation in the Fc region that decreases the ability to interact with the Fc receptor on natural killer (NK) cells. The second version, HuLuc63-LF, exhibits low levels of fucosylation in the Fc region that would result in increased binding to the Fc receptor. Compared to HuLuc63, the LF version exhibited significantly better in vivo anti-tumor activity towards, while the Ala,Ala mutant exhibited no anti-tumor activity. These data indicate that the Fc region of HuLuc63 is critical for its anti-tumor activity, and suggest ADCC as a possible mechanism of action. In vitro, HuLuc63 exhibits substantial ADCC towards L363 and OPM2 cells. The activity was dose-dependent, with increasing cytotoxicity being observed with concentrations ranging from 0.01μg/mL to10 μg/mL. Conclusions: These pre-clinical data support HuLuc63 as a new therapeutic for the treatment of MM and suggest that ADCC is part of the mechanism of action. HuLuc63 will be entering a phase I clinical study for multiple myeloma.

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

Blood ◽

10.1182/blood.v126.23.1564.1564 ◽

2015 ◽

Vol 126 (23) ◽

pp. 1564-1564 ◽

Cited By ~ 7

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.

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Identification of Chemotherapeutic Dihydromyricetin With Enhanced Anti-tumor Activity and Biosafety for Muscle Invasive Bladder Cancer

10.21203/rs.3.rs-763057/v1 ◽

2021 ◽

Author(s):

Zijian Wang ◽

Zicheng Guo ◽

Wenjie You ◽

Wang Wang ◽

Fenfang Zhou ◽

...

Keyword(s):

Bladder Cancer ◽

Macrophage Polarization ◽

Xenograft Model ◽

Postoperative Chemotherapy ◽

In Vitro Tests ◽

Promising Alternative ◽

Mesenchymal Transition ◽

Muscle Invasive ◽

Anti Tumor Activity

Abstract Background: Muscle invasive bladder cancer (MIBC) is one of the most common malignant diseases in elderly men, such as veterans. Postoperative chemotherapy plays a vital role in preventing recurrence and metastasis of MIBC. However, fewer of chemotherapeutic drugs with remarkable anti-tumor activity and biosafety are available for clinical treatment.Methods: In this work, a novel plant-derived drug, named as dihydromyricetin (DHM), was selected for postoperative chemotherapy of MIBC. The anti-tumor activity was evaluated using a series of in vitro tests, such as MTT assay, flow cytometry and western blot. Furthermore, a xenograft model of BALB/C57 nude mice was established to verify the good anti-tumor activity and biosafety of DHM in vivo. Results: DHM could effectively inhibit the proliferation, survival and migration of MIBC cell, and promote apoptosis (P<0.05). Cytotoxic macrophage polarization from M0 to M1 was promoted by DHM treatment, and the hub genes in cell cycle and apoptosis signaling pathways were differential expressed. We also found that DHM could reverse the epithelial-mesenchymal transition (EMT) of MIBC cell. The in vivo results revealed that intravenous injection of DHM with a dose of 20 mg/kg for 7 times could significantly suppress the in vivo tumorigenesis of MIBC (P<0.05), while triggered no obvious drug side effects. Conclusion: This work identified a novel chemotherapeutic DHM with remarkable anti-tumor activity and biosafety, which could serve as a promising alternative for postoperative chemotherapy of MIBC.

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